JPWO2008126401A1 - Protein refolding device - Google Patents

Abstract

An object of the present invention is to provide an inactive protein produced in Escherichia coli or the like due to non-formation of a higher-order structure, or a protein that is effective for refolding, ie, functional activation, of a protein that has been inactivated due to a change in the three-dimensional structure. It is to provide a refolding device. According to the present invention, there is provided a protein refolding apparatus comprising at least a refolding column filled with a protein refolding column filler containing a BEA-structured zeolite (zeolite beta) granulated into particles. Is done.

Description

  The present invention relates to a protein refolding apparatus used for the function activation operation / process of an inactive protein. More specifically, the present invention relates to an inactive protein because a higher-order structure is not formed, or for some reason. An apparatus for performing an operation / process for refolding a protein that has been inactivated due to a change in the three-dimensional structure and activating / regenerating the intrinsic function inherent to the protein, and activation of an inactive protein using the apparatus, that is, production of an active protein It is about production. The present invention, for example, in the technical fields of biochemicals and pharmaceutical production, refolds a higher-order unformed protein produced using a gene expression system such as Escherichia coli so that the original function / activity of the protein is improved. The present invention is useful for providing a new device that can be activated and a new function activation method using the same. Conventionally, proteins obtained by expression systems such as Escherichia coli generally have a problem that the three-dimensional structure is disordered, the protein does not have the original functions and properties, and does not exhibit activity. The equipment not only provides innovative protein production and production technology that activates the functions and activities of inactive proteins typified by the above-mentioned proteins and regenerates them into proteins with the specified functions and activities, but also makes the process a conventional technology. Compared to a large simplification.

  It is not a gene that actually acts and works in vivo, but a protein made from them. Therefore, elucidation and analysis of protein functions and structures are extremely important, for example, directly related to disease treatment and drug discovery. For this reason, various proteins are synthesized and produced by various methods, their structures are examined, and action mechanisms and roles in the living body are elucidated. Now, it is well known that the functions of proteins are determined not only by the sequence and chain length of the amino acids constituting them, but also by the ordered three-dimensional structure (higher order structure) taken by them.

  Protein synthesis is generally performed using expression systems such as Escherichia coli, insect cells, and mammalian cells. In the synthesis by insect cells and mammalian cells, the resulting protein is often soluble, with a higher order structure controlled, an ordered three-dimensional structure. However, these methods have a drawback that the operation of separation and purification is very complicated, and it takes time to obtain the target protein, resulting in an increase in cost and an extremely small amount of protein to be obtained. In contrast, protein synthesis by E. coli is easy to operate, requires less time to obtain the target protein, and does not cost much. For this reason, at present, a method using E. coli into which a gene code responsible for the synthesis of a target protein is incorporated has become the mainstream of protein synthesis, and a production process is being established.

  However, when proteins from higher organisms such as humans are synthesized in the E. coli expression system, the protein can be obtained as designed with respect to the binding sequence and number of amino acids, that is, the amino acid chain length, but the three-dimensional structure is unordered and higher order. A protein whose structure is not controlled, that is, an insoluble protein called an inclusion body in which amino acid chains are entangled is obtained. As a matter of course, the inclusion body of this insoluble protein does not have the desired function and performance and does not exhibit activity. For this reason, in the production process using E. coli, it is necessary to unwind the inclusion body, prepare a higher-order structure, and convert it into a soluble protein having an ordered three-dimensional structure, that is, refolding (rewinding) the inclusion body.

  This type of refolding is an extremely important technique that can be applied not only to the production of proteins by E. coli but also to the regeneration of proteins inactivated due to certain causes such as heat history. Therefore, this refolding has been extensively studied and various methods have been proposed, but most of them have a low refolding rate and are limited to certain limited proteins (especially specific proteins with low molecular weight). In many cases, the results of this refolding were only accidentally favorable, and this refolding is now efficient, economical, general, universal, and refolding applicable to various proteins. It ’s not the right way. Further, these methods are based on a batch method, and require a lot of manpower for a series of refolding operations.

  Under such circumstances, the present inventors studied the selective adsorption phenomenon of biopolymers by inorganic oxides such as zeolite (see Non-Patent Document 1), and in this process, the inactive protein was activated by adsorption / desorption to zeolite beta. As a result, the inventors have invented a function activation method for inactive proteins using zeolite beta (see Patent Documents 1, 2, 3, 4 and Non-Patent Document 2). However, the methods described in Patent Documents 1, 2, 3, 4 and Non-Patent Document 2 are batch systems, and zeolite beta can generally be obtained only with very fine powder particles of submicron or less. Filtration is not easy in the separation process in the adsorption / desorption process of protein to zeolite beta, the centrifuge must be used several times, and the protein activation process of the invention uses only adsorption / desorption of zeolite beta Although the process is extremely simple, the process has the disadvantage that it is complicated, cumbersome and time-consuming.

  In addition, in the conventional refolding operation / process, it is indispensable to use a chromatograph in addition to a centrifuge, which also takes a lot of time and effort, resulting in high costs. there were.

JP-A-2005-29531 JP2005-192452 JP-A-2005-220121 JP-A-2005-281267 Chem. Eur. J., Vol. 7 (2001) 1555-1560 Anal. Biochem., Vol. 348 (2006) 307-314

  The present invention relates to protein refolding that is effective for refolding, that is, functional activation of inactive proteins produced by Escherichia coli or the like due to non-formation of higher-order structures, or proteins that have been inactivated due to a change in the three-dimensional structure. Providing a device was a problem to be solved.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research and prepared a BEA structure having an unwinding function to prepare an active protein by arranging the higher-order structure of an inactive protein because the higher-order structure is disordered. We have discovered that zeolite beta (zeolite beta), which is granulated in the form of particles, can be used as a column packing material for protein refolding, thereby developing a refolding device capable of continuous processing. The invention has been completed. The refolding column filler used in the present invention is a high-order protein having a molecular weight exceeding 100,000 such as a protein not formed in a higher-order structure produced by an expression system such as Escherichia coli or a protein deactivated for some reason such as thermal history. It can be applied to unwinding various three-dimensional disordered proteins and the like with a simple operation. Therefore, according to the present invention, there is provided a protein refolding apparatus having high generality and universality and a simple and simple operation. FIG. 1 shows an example of the configuration.

That is, according to the present invention, the following inventions are provided.
(1) A protein refolding apparatus comprising at least a refolding column filled with a protein refolding column filler containing a BEA-structured zeolite (zeolite beta) granulated in a particulate form.

(2) The protein refolding apparatus according to (1), wherein the zeolite beta is granulated in a particle diameter range of 20 μm to 1000 μm.
(3) The protein refolding device according to (1) or (2), wherein the column filler for refolding comprises zeolite beta and a paste for granulating zeolite beta.

(4) To add at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor to the refolding column. The protein refolding device according to any one of (1) to (3), further comprising:
(5) Pump or natural gravity using a protein solution and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant and a refolding factor The protein refolding device according to any one of (1) to (4), comprising means for feeding the solution to a refolding column below.

(6) Pump or natural gravity of protein solution and at least one selected from protein denaturant, pH adjuster, protein SS cross-linking inhibitor, aggregation / precipitation inhibitor, surfactant and refolding factor The protein refolding apparatus according to any one of (1) to (5), comprising means for controlling the order of liquid feeding by operating a valve when the liquid is fed to the refolding column below.
(7) Pump or natural gravity at least one selected from protein solutions and protein denaturants, pH adjusters, protein SS cross-linking inhibitors, aggregation / precipitation inhibitors, surfactants and refolding factors (1) to (6) provided with means for continuously changing the mixing ratio of the solution by a pump or a valve capable of continuously changing the flow rate when the liquid is sent to the refolding column below. The protein refolding apparatus according to any one of the above.

(8) Pump or natural gravity using at least one selected from protein solutions and protein denaturants, pH adjusters, protein SS cross-linking inhibitors, aggregation / precipitation inhibitors, surfactants and refolding factors (1) to (7) provided with means for stopping the liquid feeding and controlling the equilibration process by a valve installed at the inlet / outlet of the column when the liquid is fed to the refolding column below. The protein refolding device according to any one of the above.
(9) Pump or natural gravity by pumping or at least one selected from protein solutions and protein denaturants, pH adjusters, protein SS cross-linking inhibitors, aggregation / precipitation inhibitors, surfactants and refolding factors (1) to (8) provided with means for changing the flow path by operating a valve or repeatedly passing the refolding column by a pump when the liquid is sent to the refolding column below. The protein refolding device described.

(10) Pressurization with a pump of a protein solution and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant and a refolding factor A means for passing through the refolding column under normal pressure or a state of gravity due to gravity, and a means for dividing and collecting the protein solution unwound after protein refolding ( The protein refolding device according to any one of 1) to (9).

(11) Pressurization with a pump of a protein solution and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant and a refolding factor A means for refolding the protein by passing it through a refolding column under normal pressure or gravity, and a means for detecting the protein concentration of the solution passing through the column (1 The protein refolding device according to any one of (10) to (10).

(12) (1) Means for arbitrarily setting the order of feeding various solutions passed through the refolding column, (2) Means for detecting the protein concentration of the solution passing before and after the column, and ( 3) A means for continuously and / or stepwise changing the liquid feeding speed, the liquid feeding pressure, the residence time, the mixing ratio, and the numerical values of the various solutions is provided. The protein refolding device according to any one of the above.

(13) Injecting the inactive protein into the refolding column in the protein refolding apparatus according to any one of (1) to (12), and bringing the inactive protein into contact with the protein refolding column filler A method for activating the function of an inactive protein.

The present invention relates to a protein refolding device for activating the function of an inactive protein. According to the present invention, the following effects are achieved.
(1) Universal refolding conditions that activate their original functions can be selected for a wide range of inactive proteins regardless of the type of protein.
(2) The protein of the present invention is not used because the higher-order structure produced in the expression system such as Escherichia coli is not formed. By processing activated proteins, the original functions and activities of these proteins can be activated by refolding.
(3) The apparatus of the present invention is also effective for inclusion body proteins, and is useful as an efficient method for refolding inclusion bodies using the same.
(4) The function activation method of an inactive protein by using the apparatus of the present invention is applicable to various denatured proteins regardless of the chain length / sequence of amino acids constituting the protein, and has generality and universality. Moreover, it is provided as an efficient method with a high refolding rate.
(5) The BEA-structured zeolite, ie, zeolite beta, constituting the refolding column filler used in the apparatus of the present invention is low in cost.
(6) The function activation method of an inactive protein using the apparatus of the present invention can be applied to the refolding of various three-dimensional disordered proteins including large proteins having a molecular weight exceeding 100,000.
(7) For example, by combining the protein synthesis process by the expression system of E. coli and the functional activation of the inactive protein by the apparatus of the present invention, a protein having a natural function inherent to the protein is controlled by controlling the higher order structure. A new active protein production process can be proposed and established.

Next, the present invention will be described in more detail.
In the refolding apparatus of the present invention, a column using a zeolite having a BEA structure as a column filler is an essential component. A zeolite with a BEA structure (commonly called Zeolite Beta) is also called Beta Zeolite and is typically synthesized in-house according to, for example, ordinary commercial zeolite beta, literature (Zeolites, Vol. 11 (1991) 202).・ Zeolite beta prepared, zeolite beta obtained by calcining them, zeolite beta having ammonium and various aliphatic and / or aromatic ammonium in the space of the zeolite, part of the skeletal silicon forming the zeolite Is a framework-substituted zeolite beta that has been changed to other metals, the ammonium-containing framework-substituted zeolite beta, and so on. The refolding column packing material and column can be used. The production method and properties of zeolite beta to be formed are not particularly limited.

  However, the function and ability of the zeolite beta constituting the refolding column used by the refolding apparatus of the present invention is exhibited by inertness and contact of the modified protein with the zeolite, that is, adsorption / desorption. In addition to the importance of the affinity between the zeolite beta surface and the protein of interest, the adsorption / desorption of the protein is caused by the dispersion solvent, the denaturing agent and surfactant in the dispersion solvent, the refolding factor, Since it is often affected by the pH of the dispersion solvent, etc., the refolding apparatus of the present invention uses the refolding column as appropriate depending on the target protein and the component status of the solution containing the protein. is there. The refolding ability of the refolding column often varies somewhat depending on the various zeolite betas that constitute it. Generally speaking, the refolding column packing composed of zeolite beta containing ammoniums shows higher refolding ability than the one not containing them, so that the refolding column packing and column include ammoniums. Often it is preferred to be composed of a zeolite beta containing and a framework-substituted zeolite beta containing ammoniums.

  Ammoniums to be contained in zeolite beta of the refolding column include ammoniums that easily remain in the space of the zeolite, for example, ammonium ions, mono- and di-alkyl such that the alkyl group is methyl, ethyl, propyl and butyl. , Tri- and tetraalkylammonium ions, and ammonium ions of 5-membered, 6-membered and 7-membered aliphatic amines and aromatic amines, more specifically piperidium ions, alkylpiperidium ions, pyridinium ions, alkyls Examples thereof include a pyridium ion, an aniline ion, and an N-alkylaniline ion. Basically, any ammonium can be used as long as it can enter the pores of zeolite beta. Limited to limited ammonium Not.

  The elements that form the framework of zeolite beta of the refolding column are generally silicon and oxygen, or silicon, oxygen, and aluminum. However, zeolite beta in which a part of silicon or aluminum is substituted with other elements and its fine particles are used. The substituted zeolite beta containing the ammoniums in the pores also has an inactive protein activity activation function. Typical examples of zeolite beta that can be replaced with framework silicon or aluminum include boron, phosphorus, gallium, tin, titanium, iron, cobalt, copper, nickel, zinc, chromium, vanadium, and the like. However, any material may be used as long as it does not basically destroy the structure of zeolite beta. In addition, the substitution amount may be any amount as long as it does not destroy the structure of zeolite beta. The substitution zeolite beta is inactive or is used for refolding that exhibits the refolding function of a denatured protein. Can be a column filler.

  Zeolite beta used in the present invention is excellent in thermal stability and chemical stability, and is a substance that is inexpensive and has a low environmental load. Therefore, the refolding apparatus of the present invention can be used for, for example, biochemical production, It is extremely useful for pharmaceutical manufacturing and its economic effects are immeasurable.

  Since zeolite beta can generally be obtained only with very fine powder particles of submicron or less, it is problematic to use zeolite beta itself as a refolding column filler. For example, when zeolite beta that is not granulated is packed in a column, the particle size causes the filter to pass through the filter attached to the outlet side of the column, adversely affect the pump part of the device, or easily clog the filter. It is fully expected that it will not be used as a column. Also, zeolite beta that does not perform granulation is packed into a column, and a large pressure is required to pass the solution through the column, which may place unnecessary load on the liquid feed pump and the like. is expected. In view of this situation, granulation of zeolite beta is indispensable for use as a column filler. In the refolding apparatus of the present invention, a refolding column using granulated zeolite beta is used. This column is shown in FIG.

  The particle size when using zeolite beta as a column filler is determined by the viscosity and concentration of the solution, the performance of the pump, etc., as long as the solution can permeate at an appropriate pressure so as to function as a column. Although it varies depending on the form of use and is appropriately selected, in view of the pressure resistance of the existing column and the performance of the pump, it is preferably in the range of 20 to 1000 μm.

  The column filler for refolding used in the present invention is preferably composed of a zeolite having a BEA structure, so-called zeolite beta, and a paste (granulating agent) for granulating the zeolite. Generally speaking, since the substance called zeolite is poor in self-sintering properties, it is often difficult to form by itself, so the paste material is used for the production of granules, that is, the design and control of shape and shape. In general, the degree of freedom is high and advantageous in many cases.

  However, the design / control method, that is, the production method of the shape and shape of the granulated zeolite beta, which is granulated, varies depending on the utilization method and usage form of the granulated body, and is appropriately selected. Therefore, all known methods can be used for the production of the granulated body, which is appropriately selected or used in combination. Although there is no need for mention, there are the following as a method for producing the granulated body, that is, a design / control method of the shape and shape. In the production of granules, zeolite beta granulation with water-insoluble adhesive, dry gel conversion method and solid phase conversion method (Stud. Surf. Sci. Catal. Vol. 125 (1999) 1-12, and surface , Vol. 37 (1999) 537-557), agglomeration of zeolite beta, adhesion and molding of zeolite beta with inorganic powder such as alumina, and granulation of zeolite beta by adhesion to the core substance It is possible, but not limited to these.

  On the other hand, since zeolite is a substance with extremely poor self-sinterability, granulation by sintering is extremely difficult. When trying to sinter, alumina is often used as a sintering aid. However, when alumina is used as a sintering aid, a reaction by heat proceeds between zeolite and alumina, and a new phase is formed. This new phase is often a substance that is essentially different from zeolite and is not likely to be suitable as a refolding column filler or likely not to have this function. Therefore, granulation of zeolite beta by this kind of sintering is not highly recommended but is not excluded.

  As a preferred example of the granulation method using the paste material, a method using a bread granulator, which is a general granulation method, is well known. The raw material powder is loaded into a pan-like container having an inclination angle on the rotation shaft, and is rotationally stirred. By spraying or dripping the paste material onto the raw material powder, aggregation and adhesion of the raw material particles are promoted and granulation is performed. The size and dimensions of the bread, the rotation speed and the inclination angle, the addition method and the addition speed of the paste material vary depending on the use method, usage form, and production amount of the granule, and are appropriately selected. is there.

  The form and shape of the granulated body are appropriately selected according to the method of using and using the granulated body, such as a spherical shape, a lump shape, a scale shape, and a porous shape. In particular, as for the paste material, any material may be used as long as it is basically insoluble in water and does not adversely affect the protein. For example, acetylcellulose is a promising example. It is promising to use an acetone solution. Nitrocellulose and polystyrene resins are also promising as well. It is promising to use nitrocellulose in a state in which it is dissolved in acetone or a solvent containing acetone as a main component, and in a state in which a polystyrene resin is dissolved in a solvent containing ethyl acetate as a main component.

  When zeolite beta is granulated by the granulation method, granulation proceeds according to the amount of acetylcellulose added, and a larger particle size can be obtained. However, if too much glue material is added, the surface of the zeolite beta may be covered by the glue material and the protein refolding function may be lost. Although it depends on the conditions at the time of production, it is preferable to obtain good particles as a refolding column filler in the range of 0.2 to 50% by weight in the dry state of the paste material. Can do.

  It is extremely inconvenient in practical use that the refolding column has a performance difference between lots. The difference in performance between lots of the refolding column has a large influence on the amount and packing state of the packed packing material, and the condition, such as the particle size distribution and particle shape of the packing material. In order to eliminate this inconvenience, it is necessary to control the particle size distribution and particle form of the granulated body, but the method varies depending on the method of use and usage of the granulated body and is appropriately selected. Is. Therefore, all known methods can be used to control the particle size distribution and particle morphology of the granulated body, and are appropriately selected or used in combination. Although no detailed explanation or reference is required, the method for controlling the particle form of the granulated body can be achieved by controlling the conditions during granulation. In addition, as a method for controlling the particle size distribution of the granulated body, there are general methods such as classification using a sieve and classification using a fluid. According to the method using a sieve, the particle size distribution can be controlled by the standard of the prepared sieve.

  Reagent group that activates the function of the inactive protein used by the apparatus of the present invention, that is, the protein that is the target of the refolding apparatus is all inactive proteins with no higher-order structure, The three-dimensional structure obtained in the system is a disordered protein, a so-called inclusion body, or a protein deactivated due to a certain cause such as thermal history. The apparatus of the present invention refolds the three-dimensional structure of the protein in the process of adsorption / desorption to the refolding column comprising zeolite beta in the apparatus, and activates / provides the original function of the protein. However, the present ability of the refolding column is not necessarily limited thereto, but is usually exhibited by the following operation. In other words, functional activation of the inactive protein is performed by the following operation. First, the protein is dispersed and dissolved in a solution containing a denaturing agent, a surfactant, etc., and then the protein is adsorbed to the refolding column by injection into the refolding column, and then the refolding column is used. The procedure is to desorb the protein from the column.

  In general, the protein dispersion solvent before adsorption onto the refolding column is produced in an expression system such as Escherichia coli, and the protein is usually used in an aqueous solution and is inactivated. In many cases, water is preferably used because it is often in an aqueous solution. However, the present invention is not necessarily limited to this, and there is basically no problem as long as it does not cause a reaction with the protein and does not change the three-dimensional structure of the protein into an unintentional form. In some cases, these solvents can be used alone or mixed with water. Typical examples of this type of solvent include, but are not limited to, monohydric and polyhydric alcohols and polyethers.

  The adsorption / desorption of the protein is generally performed in the presence of a denaturing agent, a surfactant, a pH adjusting agent, a refolding factor, etc. in order to easily unwind the entangled protein chain length such as an inclusion body, And / or in order to cleave the S—S bond (cross-linking) generated unintentionally in the protein chain length, it is carried out in the presence of a certain reducing agent or redox reagent. Therefore, the apparatus of the present invention uses a refolding column made of zeolite beta, a denaturant or a pH adjuster as necessary as a constituent element, and in addition to these, the protein of the protein from the refolding column is used. A solution containing a refolding factor and / or a surfactant for preventing desorption promotion and refolding after refolding, and an SS crosslinking formation inhibitor (inhibition) as necessary is used.

Typical examples of this type of modifier and pH adjuster used by the apparatus of the present invention include, for example, guanidine hydrochloride and urea for the former, and trisaminomethane hydrochloride (TrisHCl) and 4- (2-hydroxyethyl) for the latter. ) -1-Piperazineethanesulfonic acid (4- (2-hydroxyethyl) -1-piperazineethanesulfonic
acid: HEPES), 2-monoloninoethanesulfonic acid (MES), 3-monoholinopropanesulfonic acid (MOPS), etc. Rather, anything having a similar action can be used.

  Typical examples of the refolding factor and surfactant used by the apparatus of the present invention include polyethylene glycol (PEG 20000, PEG 800, PEG 200, PEG 3350, etc.), Ficol 170, Ficol 1400, polyphosphoric acid, sodium dodecyl sulfate (SDS), sucrose, Examples include, but are not limited to, glucose, glycerol, inositol, cyclodextrin, amylose, Dextran T-500, Tween20, Tween40, Tween60, NP-40, SB3-14, SB12, CTAB and TritonX-100. Anything having a similar action can be used.

  As a reducing agent that cleaves the S—S bridge formed unintentionally and returns it to its original structure, 2-mercaptoethanol, dithiothreitol, cystine, glutathione, or thiophenol is usually used because it is inexpensive and readily available. However, the present invention is not limited to this, and anything that performs the same function can be used.

  As a matter of course, when the protein chain length is easily unraveled or when the S—S crosslinking is not generated unintentionally, it is not always necessary to use a denaturant, a surfactant, and / or a reducing agent. Existence is not always essential, and is appropriately selected according to the situation. The amount of the solution component used in the apparatus is appropriately determined according to the situation when it is used, but the apparatus of the present invention usually has a refolding column made of zeolite beta, guanidine hydrochloride (modifier) and TrisHCl and HEPES (pH adjuster) are used as solution components, and 2-mercaptoethanol and one or two of the refolding factor and surfactant are used.

  In general, in the protein desorption process during the refolding operation / process using this device, substitution adsorption by the reagent (folding factor or surfactant) used by the device is usually used. Any operation can be applied as long as it does not hinder the function activation after the desorption. There is no particular limitation. Therefore, pH change, temperature change, etc. can be used, and these can be used in combination with displacement adsorption.

  By the way, as a substance that promotes desorption of the protein during substitution adsorption, conventionally, salts such as alkali halides have been frequently used in column chromatography elution, and when these are used together, a remarkable effect can be obtained. There are also many. In addition, when using the apparatus of the present invention, if there is no particular problem or trouble such as a reaction between reagents, some of the constituent reagents can be combined in advance to form one reagent. Examples include HEPES, alkali halides (eg sodium chloride), 2-mercaptoethanol, refolding factors (eg polyethylene glycol PEG 20000, PEG 800, PEG 200, PEG 3350, Ficol 170 or β-cyclodextrin) In addition, a solution comprising a surfactant (for example, Tween 20, Tween 40, Tween 60, NP-40, or Triton X-100) can be combined as a refolding buffer to be one of the constituent reagents used by the apparatus of the present invention. This is often a great convenience in refolding operations / processes.

  When the protein is unwound from the refolding column in the unwound state, the protein may aggregate and precipitate depending on the concentration and the composition / state of the solution. In order to avoid such unintentionally generated aggregation / precipitation, arginine, whose effect is well known, is used, but the present invention is not limited to this, and anything that performs the same action can be used. Of course, if the protein is difficult to agglomerate in the unwound state, or if unintentional aggregation / precipitation does not occur, it is not always necessary to use an anti-aggregation agent, so their presence is always essential. It is not limited to this, and is appropriately selected according to the situation. Moreover, also when using them, those quantity will be suitably determined according to a condition.

  These solution groups are indicated by 4, 9, and 10 in FIG. A solution group containing a protein denaturant, a pH adjuster, a protein SS crosslinking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor corresponds to 4 in FIG. The solution containing the pH adjuster corresponds to 9 in FIG. The protein solution (which may contain a denaturant or a surfactant) corresponds to 10 in FIG.

  Furthermore, in order to promote adsorption of the protein to the refolding column in the apparatus or desorption from the column, various additional operations can be performed in combination with the above operation. Typical examples of such operations include irradiation of ultrasonic waves and microwaves, and application of magnetic fields and electric fields. These operations are performed by the site indicated by 8 in FIG. By the procedures and operations using the apparatus of the present invention described above, the protein unwinding ability of the refolding column will be demonstrated to a high degree, and the higher order structure produced using an expression system such as Escherichia coli. Refolding occurs in unformed proteins as well as proteins that have been deactivated for some reason, and the functions that these proteins originally have are quickly activated.

  In the apparatus, the protein is dispersed and dissolved in a solution containing a denaturant, a surfactant, and the like, and then the protein is adsorbed to the refolding column by injection into the refolding column, and then the refolding column is used. This is performed by a procedure for desorbing the protein from the folding column, and the function of the inactive protein is activated. In order to perform this operation continuously, the apparatus uses, as essential components, a pump for sucking and feeding the solution and a valve for switching the type and flow of the solution. A site having these functions is indicated by 1 in FIG. In general, there is a liquid chromatography apparatus as an apparatus capable of performing such an operation. This apparatus is equipped with a refolding column as an essential component, and is an apparatus intended to operate the refolding column under optimum conditions.

  As a pump, it changes with the utilization methods and usage form of a refolding column, and is selected suitably. Therefore, as the types and types of pumps, all known methods can be used, and are appropriately selected or used in combination. Although it is not necessary to refer to it, it is preferable to apply it. To mention a few examples, when using an open column type refolding column, even a simple structure such as a peristaltic pump is used. In the case of an inline column type refolding column that can be applied, there is a double plunger reciprocating pump with a control mechanism in that a pulsating flow hardly occurs. These are indicated by 2 in FIG.

  The specifications of the switching valve also vary depending on the method of use and usage of the refolding column, and are appropriately selected. Therefore, as the types and types of switching valves, all known methods can be used, and are appropriately selected or used in combination. Therefore, there is no particular limitation, and a detailed description is provided. Multi-valve type such as three-way valve or six-way valve, which does not need to be mentioned or mentioned but is preferred to be applied. There are other valves. Needless to say, a type that is driven by electric power and can detect the valve position by an electrical signal or the like is preferable. The site | part which has these functions is shown by 3 in FIG.

  It is often preferable that the solution containing the protein refolded by the refolding apparatus is appropriately collected. The concentration of the protein solution that is refolded from the protein refolding column is easily expected to change in response to a continuous or discontinuous change in the composition of the solution flowing through the refolding column. Therefore, it is desirable to inject into a separate container by a fixed volume. The solution sorting apparatus or sorting mechanism varies depending on the type of protein, the method of using the refolding apparatus, and the usage pattern, and is appropriately selected. Accordingly, as the type / form of the sorting device or the sorting mechanism, all known methods can be used, and are appropriately selected or used in combination. Moreover, although it does not require any detailed explanation or reference, it is preferable to apply the application. For example, a table on which a large number of tubes are set is automatically driven and fixed from the top of each individual tube. There is an apparatus that dispenses a predetermined volume by dropping an amount of a solution. Sites having these functions correspond to 11 and 12 in FIG.

  It is often preferred that the protein concentration of the solution containing the protein refolded by the refolding device is measured in real time. The concentration of the protein solution that is refolded from the protein refolding column is easily expected to change in response to a continuous or discontinuous change in the composition of the solution flowing through the refolding column. Therefore, it is desirable that the refolding apparatus is equipped with a mechanism that measures the protein concentration in the solution in real time in order to properly operate the valve and dispense the solution. This detection system varies depending on the method of use and usage of the refolding apparatus, and is selected as appropriate. Therefore, as the types and types of detectors, all known methods can be used, and are appropriately selected or used in combination. Therefore, there is no particular limitation, and a detailed description is provided. Although there is no need for mention, mention is preferably made of a method for measuring absorption of ultraviolet light at 280 nm. The site | part which has these functions is shown by 5 in FIG.

  The refolding apparatus can arbitrarily set the liquid feeding order of various solutions to be used, and the liquid feeding speed, liquid feeding pressure, residence time, mixing ratio of various solutions, and continuous and / or stepwise measurement of those values. By performing such changes, the protein can be efficiently refolded and recovered. In order to exhibit this feature more efficiently, it is preferable to have a function capable of setting the various conditions described above. The method and mechanism vary depending on the method of use and usage of the refolding apparatus, and are appropriately selected. Therefore, as a control method and mechanism, all known methods can be used, and are appropriately selected or used in combination. Therefore, the control method and mechanism are not particularly limited. Although it is not necessary to make a reference, examples of preferable applications include pumps, valves, protein concentration detection by computers, and automatic control of sorting devices. A site having these functions is indicated by 13 in FIG.

  The present invention will be specifically described based on the following examples, but the present invention is not limited by the following examples.

  In the following examples, functional activation of E. coli expression system production protein and denatured protein will be described, but the present invention is not limited or restricted by the examples.

(1) Preparation of column filler and column (a) Preparation of refolding column filler (granulation)
Zeolite beta powder is put into a bread granulator or a granulator whose bread mold part is changed into a cylindrical shape, and an acetone solution of 1-2% by weight acetylcellulose is sprayed using a sprayer or an airbrush to granulate Went. The rotational speed of the granulator is 60 revolutions / minute, and the inclination angle of the pan and the cylindrical container is 45 ° C. However, these conditions are appropriately adjusted depending on the amount of the raw material powder to be loaded. The concentration of acetyl cellulose is suitably 1 to 2% by weight. If the concentration is higher than this, the viscosity of the solution becomes high and spraying becomes difficult. In the range of 3 to 20% of the final acetylcellulose with respect to the weight of the raw material powder, a preferable granular powder can be obtained. As a matter of course, the particle diameter tends to increase as the acetylcellulose content increases.

(B) Classification of refolding column filler Since the granulated zeolite beta has a particle size distribution, it is classified. A general method using a sieve can be applied. However, since zeolite beta has a small primary particle size and easily absorbs moisture in the air, it tends to cause aggregation. In many cases, classification by ordinary sieving is difficult. In many cases, classification is facilitated by suspending the granulated product with ultrapure water and sieving it in a slurry state. In this method, if the particle size is 50 μm or more, classification can be easily performed, and the particle size distribution can be controlled by the standard of the prepared sieve. For example, if powders that pass through a 100 μm sieve and do not pass through a 75 μm sieve are collected, the particle size distribution falls within the range of 75 to 100 μm. The particle size distribution can be controlled in a similar manner.

(C) Packing the column packing material for refolding into the column The produced granular zeolite beta is suspended in ultrapure water and packed into the column using gravity sedimentation. Further, deaeration is performed by putting it in a vacuum desiccator or the like to perform a depressurization process, thereby ensuring a filled state without voids. Filling in a dry state is possible, but considering the convenience of subsequent use, it is more advantageous to be in a coexistence state with ultrapure water. Both open column and in-line column are packed by the same method. By using natural sedimentation by gravity, if the particle size distribution is uniform, a similar packed state can be realized, and the difference in characteristics between lots as a column can be uniformed.

  Packing into an open column uses a polyprep chromatography column manufactured by Bio-Rad Laboratories as a representative column, and about 1 to 2 g (1 to 2 ml) of a packing material in a slurry state in a mixed state with ultrapure water. inject. Wait for spontaneous sedimentation due to gravity to stabilize the filler. Then, open the outlet at the bottom of the column and discard the extra ultrapure water. Store or use the column in a wet state with ultrapure water.

  For filling the in-line column, a Tricon column set manufactured by GE Healthcare is used as a representative column. A glass tube of the same diameter is connected through an adapter, and a slurry in a slurry state is injected in a suspension with ultrapure water. Wait for spontaneous sedimentation due to gravity to stabilize the filler. After removing the adapter, deaeration is performed by applying a vacuum treatment in a state filled with ultrapure water. Store or use the column in a wet state with ultrapure water.

  For comparison, a zeolite beta without granulation was packed in a column. As a result, it was clarified that the filter attached to the outlet side of the column easily clogs and does not serve as a column. In addition, zeolite beta that does not perform granulation is packed into a column, and a large pressure is required to pass the solution through the column. This imposes an unnecessary load on the liquid feed pump, etc. It has been shown that granulation of zeolite beta is essential for use as a filler.

(2) Preparation of sample and the like (a) Denatured protein solution RNase A and lysozyme, which are available as reagents, were used as the protein to be activated. In addition, GFP (green fluorescent protein) and LDH (lactate dehydrogenase) were used as inclusion bodies expressed from E. coli. Both the reagent and the inclusion body are dissolved in a 6M guanidine hydrochloride solution to prepare a 1 mg / ml solution while measuring the concentration.

(B) Refolding buffer Generally, as an example, 50 mM HEPES pH 7.5 / 0.5 M NaCl / 20 mM 2-mercaptoethanol / 0.5 (w / v)% polyethylene glycol 20000 (refolding factor) is used as the refolding buffer. / 1 (v / v)% A solution having a composition of Tween 20 (surfactant) was used.

(3) Protein concentration measurement method The Bradford method and the BCA method were appropriately used for the protein concentration measurement. The concentration was determined by colorimetric analysis using a calibration curve after a predetermined operation using a 1.5 ml tube or a microplate.

(4) Protein Activity Measurement Method (a) Lysozyme Activity Evaluation Lysozyme activity was evaluated using the lytic activity of Micrococcus lysodeikticus as an index. A reaction solution was prepared by suspending freeze-dried cells of Micrococcus lysodeikticus in 0.1 M phosphate buffer (pH 7.0) and adjusting the absorbance at a wavelength of 450 nm to 1.0. After pre-incubating the reaction solution at 25 ° C., a sample containing lysozyme was added to the reaction solution, and the decrease in absorbance at a wavelength of 450 nm was measured. The activity value was calculated with 1 unit of activity that decreases the absorbance at a wavelength of 450 nm by 0.001 per minute.

(B) Activity evaluation of RNase A The activity of RNase A was evaluated as follows. Cytidine 2 ′, 3′-cyclic monophosphate dissolved in 20 mM phosphate buffer (pH 7.5) so as to have a concentration of 0.5 mg / ml was used as a reaction solution. After pre-incubating the reaction solution at 25 ° C., a sample containing RNase A was added to the reaction solution, and the increase in absorbance at a wavelength of 286 nm was measured. The activity value was calculated with 1 unit of activity that increases the absorbance at a wavelength of 280 nm by 0.001 per second.

(C) Evaluation of GFP activity The activity of GFP (green fluorescent protein) was evaluated based on the fluorescence intensity emitted by GFP. GFP in 50 mM Tris-HCl buffer (pH 7.5) was excited at a wavelength of 490 nm, and the intensity of fluorescence observed at a wavelength of 510 nm was measured with a fluorescence spectrophotometer. The intensity of fluorescence emitted by the refolded GFP was calculated as a relative value with the same concentration of unmodified GFP as a control, and the activity was evaluated.

(D) Evaluation of LDH activity The activity of LDH (lactate dehydrogenase) was evaluated by the reduction of NADH in the reaction catalyzed by LDH (pyruvate + NADH → lactic acid + NAD). Since NADH has an absorption at a wavelength of 340 nm, the enzyme activity can be measured by measuring the decrease in absorbance. The reaction solution was 0.1 mM NADH and 100 mM MES buffer containing 100 mM pyruvic acid, and preincubated for 10 minutes at 30 ° C. Thereafter, the sample containing LDH was mixed with the reaction solution, and the decrease in absorbance at a wavelength of 340 nm was measured. The activity value was calculated with 1 unit of activity that decreases the absorbance at a wavelength of 340 nm by 0.001 per second.

(5) Refolding by open column (a) Refolding example of GFP 20 mg of filler is packed in an open column having a column effective part of 0.8 × 4 cm. In this case, a filler having a particle size distribution of 75 to 150 μm was used. Each solution was injected or dropped using a peristaltic pump capable of controlling the flow rate and flow rate. First, after opening the outlet at the bottom of the column, the open column is washed with 1 m of 6M guanidine hydrochloride solution. Thereafter, 1 ml of a 6M guanidine hydrochloride solution in which 3 mg of GFP is dissolved is added, and the solution is added dropwise. By this operation, denatured GFP is adsorbed to the filler. Add 10 ml of 1 mM Tris-HCl pH 7.5 and wash the packing through the column. These operations can be automated by performing pump and valve operations with a computer. The refolding buffer is added in a total volume of 2 ml, but the solution that has passed through the column is also dispensed in 0.2 ml portions by automatically changing the tube. The collected solution was allowed to stand overnight, and then the protein concentration and activity were evaluated.

  FIG. 2 shows the measurement results of the activity and concentration of the collected protein solution. By passing 2 ml of the refolding buffer through the column, it corresponds to the refolding buffer that has passed through each 0.2 ml open column from which fractions Nos. 1 to 10 in the figure have been collected. The activity of the protein in each fraction and the concentration of the separated protein solution from the third to the sixth were shown. From the GFP concentration of each fractionated solution, it can be seen that about 20% of GFP is recovered from the filler only by the third to sixth fractionated solution. Since the GFP collected after refolding in this fraction has a relatively high protein concentration and can ensure the accuracy of evaluation, the activity was evaluated by the intensity of fluorescence emission. The intensity of the fluorescence emitted by the refolded GFP is about 600 to 1100 LU (LU: a unit indicating the relative intensity of fluorescence), and the value of unmodified GFP at the same concentration, approximately 5000 LU, is 20 It can be seen that the recovery of activity is around%. It can be seen that the GFP refolded by the column packing recovers good activity.

(B) Refolding example of lysozyme 500 mg of filler made into a slurry with ultrapure water is packed into an open column having a column effective part of 0.8 × 4 cm. In this case, a filler having a particle size distribution of 300 to 500 μm was used. Each solution can be injected or dropped using a peristaltic pump capable of controlling the flow rate and flow rate. First, after opening the discharge port at the bottom of the column, ultra-pure water is injected to clean the open column. Thereafter, 5 ml of a 6M guanidine hydrochloride solution in which 5 mg of lysozyme is dissolved is added, and the solution is added dropwise. Ultrapure water replaces the lysozyme solution, and the denatured lysozyme is adsorbed by the filler. Add 1 ml of 6M guanidine hydrochloride solution and wash the packing material through the column. Further, 2 ml of ultrapure water is passed through the column to wash the packing material. Thereafter, refolding buffer is added to the column. These operations can be automated by performing pump and valve operations with a computer. The refolding buffer is added in a total volume of 5 ml, but the solution that has passed through the column is dispensed 1 ml at a time by automatically changing the tube. The protein concentration and activity of the collected solution were evaluated.

  The concentration of the collected protein solution was measured. Although depending on the speed at which the solution is passed through the column, when about 1 minute was added for 1 ml, 70% or more of lysozyme was adsorbed and held by the filler. When the dropping speed was increased, the unadsorbed amount tended to increase. Most of the adsorbed protein was recovered by passing the refolding buffer through the column. The activity of the refolded lysozyme was evaluated from the lysis characteristics. As a result, the lytic activity of lysozyme was confirmed.

  FIG. 3 shows the measurement results and concentration of lysozyme in the collected liquid. In the figure, F1 to F5 are numerical values of lysozyme recovered by refolding. It turns out that the specific activity of 60-100 unit / mg is shown. It can be seen that the activity is restored by the refolding operation. Among 5 ml of 6M guanidine hydrochloride solution in which 5 mg of lysozyme was dissolved, some of the lysozyme passed through the open column as it is (corresponding to FT in the figure), but the recovery of the activity was poor for the amount, and the column It can be seen that lysozyme that has been refolded with a filler has a better recovery of activity.

(6) Refolding by in-line column (a) Standard operation method A glass column or the like having both ends sealed with a seal and having a function of connecting to a tube is used. As a representative, a Tricon column set and a Tricon 5/20 column manufactured by GE Healthcare were used. 150 mg of the filler classified into a range of 75 to 100 μm by granulation is filled in a slurry form with ultrapure water. This column is mounted on an FPLC, for example, AKTA10S manufactured by GE Healthcare. The protein solution is passed through the column at a predetermined flow rate by the pump of the FPLC apparatus. After adsorbing the protein, the column is washed with ultrapure water or the like. The protein is recovered by passing through a refolding buffer. The solution that has passed through the column is generally recovered by fractionation with a fraction collector. The protein concentration and activity of the collected solution are evaluated.

(B) Refolding Example of LDH The inclusion body LDH expressed by E. coli is dissolved in a 6M guanidine hydrochloride solution containing an appropriate buffer as a denaturing buffer to obtain a 1 mg / ml protein solution. First, a denaturation buffer containing no protein is passed through the column for equilibration. Next, 10 ml of the protein solution was added at a flow rate of 0.3 ml / min. Through the column to adsorb the protein. Thereafter, the column is washed with a denaturing buffer, and further, the column is washed with a washing buffer not containing guanidine hydrochloride to wash away the denaturing buffer, and to wash away an impure component such as unadsorbed protein. The refolding buffer is then passed through the column and the protein is recovered.

  FIG. 4 shows a graph corresponding to a series of operations. The solid line shows the protein concentration measured from the absorption of ultraviolet light with a wavelength of 280 nm for the solution coming out of the column. The broken line is the activity measurement result of the collected protein solution. First, when the protein solution is passed through the column, adsorption saturation occurs, and it can be seen that the protein is gradually passing through. Next, in the washing process, unadsorbed or impure substance elution is confirmed, but it is understood that these do not show activity. It can also be confirmed that the protein is recovered by flowing the refolding buffer, and that the protein has recovered its activity. That is, it was confirmed that the protein dissolved in the denaturing buffer was adsorbed to the column filler, and after washing, the refolded active protein was recovered by the refolding buffer that was displaced and flowed. For RNase A and GFP, the protein can be recovered by the same operation. Depending on the setting of conditions and the total amount handled, these operations can be completed in tens of minutes to hours.

  As shown in the above Examples, it has been found that by using the protein refolding apparatus of the present invention used for protein refolding, the intrinsic activities of a plurality of proteins can be obtained quickly by an extremely simple operation. The protein refolding apparatus of the present invention is useful as a protein refolding apparatus having high generality and universality that can be applied to various high-order structure unformed and denatured / inactivated proteins, and its application is shown in Examples. However, the present invention is not limited to proteins that can be applied, and can be applied to any protein.

  The present invention relates to a protein refolding apparatus useful for functional activation of an inactive protein. According to the present invention, the original function of a protein that is inactive because the higher-order structure produced in an expression system such as Escherichia coli is not formed, or a protein that has been inactivated due to a change in the three-dimensional structure due to a certain cause. The activity can be activated by refolding. This method is useful as a method for efficiently and easily refolding an inclusion body. Furthermore, according to the present invention, an efficient refolding apparatus that can be applied to various proteins and has generality, universality, and a high refolding rate can be provided. Zeolite beta constituting the protein refolding column filler used in the present invention is a low-cost and low environmental load substance. The column packing material for protein refolding used in the present invention is effective for refolding various conformationally disordered proteins including large proteins having a molecular weight exceeding 100,000. Therefore, by further combining, for example, a protein synthesis process using an E. coli expression system and the protein refolding apparatus of the present invention, a protein having inherent functions inherent to the protein with a higher-order structure controlled is produced. A new active protein production process system can be constructed.

FIG. 1 is a block diagram showing the mechanism of a protein refolding apparatus according to the present invention. FIG. 2 shows GFP refolding in an open column. FIG. 3 shows lysozyme refolding in an open column. FIG. 4 shows refolding in the flow system.

Explanation of symbols

1 Switching valve with variable flow rate 2 Liquid feed pump with variable flow rate 3 Switching valve 4 Protein denaturant, pH adjuster, protein SS cross-linking inhibitor, aggregation / precipitation inhibitor, surfactant and refolding factor Solution group 5 Protein concentration detector 6 Stop valve 7 Protein refolding column 8 Ultrasonic wave, microwave, magnetic field, electric field application device 9 pH adjuster cleaning solution 10 Protein solution 11 Dispensing device 12 Dispensing solution Collection container group 13 Control computer

Claims (13)

A protein refolding apparatus comprising at least a refolding column filled with a protein refolding column filler containing a zeolite having a BEA structure (zeolite beta) granulated into particles. The protein refolding apparatus according to claim 1, wherein the zeolite beta is granulated in a particle diameter range of 20 µm to 1000 µm. The protein refolding apparatus according to claim 1 or 2, wherein the refolding column filler comprises zeolite beta and a paste for granulating the zeolite beta. A means for adding at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant and a refolding factor to the refolding column; The protein refolding device according to any one of claims 1 to 3, further comprising: A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pumped or removed under natural gravity. The protein refolding device according to any one of claims 1 to 4, further comprising a means for feeding the solution to a folding column. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pumped or removed under natural gravity. The protein refolding device according to any one of claims 1 to 5, further comprising means for controlling the order of liquid feeding by operating a valve when the liquid is fed to the folding column. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pumped or removed under natural gravity. 7. The apparatus according to claim 1, further comprising means for continuously changing a mixing ratio of the solution by a pump or a valve capable of continuously changing a flow rate when the liquid is fed to the folding column. Protein refolding device. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pumped or removed under natural gravity. A means for stopping the liquid feeding and controlling the equilibration process by a valve installed at the inlet / outlet of the column when the liquid is fed to the folding column. The protein refolding device described. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pumped or removed under natural gravity. The protein refolding according to any one of claims 1 to 8, further comprising means for changing the flow path by operating a valve or repeatedly passing the refolding column by a pump when the liquid is fed to the folding column. apparatus. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pressurized with a pump or gravity. 2. Means for passing through a refolding column under normal pressure conditions according to 1 and means for dividing and collecting the unwound protein solution after protein refolding. The protein refolding apparatus according to any one of 9. A protein solution, and at least one selected from a protein denaturant, a pH adjuster, a protein SS cross-linking inhibitor, an aggregation / precipitation inhibitor, a surfactant, and a refolding factor are pressurized with a pump or gravity. 11. A means for performing protein refolding by passing through a refolding column under normal pressure conditions according to claim 1, and means for detecting the protein concentration of the solution passing through the column. The protein refolding apparatus according to any one of the above. (1) Means for arbitrarily setting the order of feeding various solutions passed through the refolding column, (2) Means for detecting the protein concentration of the solution passing before and after the column, and (3) the above The apparatus according to any one of claims 1 to 11, further comprising means for performing continuous and / or stepwise changes in the feeding speed, feeding pressure, residence time, mixing ratio, and numerical values of various solutions. The protein refolding device described. An inactive method comprising introducing an inactive protein into the refolding column in the protein refolding device according to any one of claims 1 to 12 and bringing the inactive protein into contact with the protein refolding column packing material. Protein function activation method.

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