CN113720812A - Method for measuring protein solubility - Google Patents
Method for measuring protein solubility Download PDFInfo
- Publication number
- CN113720812A CN113720812A CN202010454423.6A CN202010454423A CN113720812A CN 113720812 A CN113720812 A CN 113720812A CN 202010454423 A CN202010454423 A CN 202010454423A CN 113720812 A CN113720812 A CN 113720812A
- Authority
- CN
- China
- Prior art keywords
- protein
- sample
- rls
- concentration
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 108090000623 proteins and genes Proteins 0.000 title claims abstract description 146
- 102000004169 proteins and genes Human genes 0.000 title claims abstract description 146
- 238000000034 method Methods 0.000 title claims abstract description 30
- 239000002904 solvent Substances 0.000 claims abstract description 27
- 239000002245 particle Substances 0.000 claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 4
- 239000007787 solid Substances 0.000 claims abstract description 3
- 239000012528 membrane Substances 0.000 claims abstract 2
- 230000004044 response Effects 0.000 claims description 19
- 238000001228 spectrum Methods 0.000 claims description 12
- 238000010790 dilution Methods 0.000 claims description 11
- 239000012895 dilution Substances 0.000 claims description 11
- 238000004458 analytical method Methods 0.000 claims description 10
- 238000000295 emission spectrum Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 claims description 10
- 239000007853 buffer solution Substances 0.000 claims description 9
- 238000004090 dissolution Methods 0.000 claims description 9
- 230000005284 excitation Effects 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 4
- 238000012886 linear function Methods 0.000 claims description 4
- 230000001360 synchronised effect Effects 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000013459 approach Methods 0.000 claims description 2
- 238000002189 fluorescence spectrum Methods 0.000 claims description 2
- 238000005070 sampling Methods 0.000 claims description 2
- 238000001209 resonance light scattering Methods 0.000 description 71
- 230000002776 aggregation Effects 0.000 description 19
- 238000004220 aggregation Methods 0.000 description 19
- 239000000872 buffer Substances 0.000 description 7
- 231100000673 dose–response relationship Toxicity 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 241000235048 Meyerozyma guilliermondii Species 0.000 description 5
- 108010092464 Urate Oxidase Proteins 0.000 description 5
- 238000003259 recombinant expression Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 108091003079 Bovine Serum Albumin Proteins 0.000 description 2
- 108010090804 Streptavidin Proteins 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- 229940098773 bovine serum albumin Drugs 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 238000004440 column chromatography Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000008176 lyophilized powder Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000012982 microporous membrane Substances 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000001954 sterilising effect Effects 0.000 description 2
- 238000004659 sterilization and disinfection Methods 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 102000007056 Recombinant Fusion Proteins Human genes 0.000 description 1
- 108010008281 Recombinant Fusion Proteins Proteins 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000001261 affinity purification Methods 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000012742 biochemical analysis Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004587 chromatography analysis Methods 0.000 description 1
- 238000010367 cloning Methods 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000004925 denaturation Methods 0.000 description 1
- 230000036425 denaturation Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 102000034238 globular proteins Human genes 0.000 description 1
- 108091005896 globular proteins Proteins 0.000 description 1
- 238000000703 high-speed centrifugation Methods 0.000 description 1
- 230000036512 infertility Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 238000005374 membrane filtration Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000005220 pharmaceutical analysis Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011175 product filtration Methods 0.000 description 1
- 230000004845 protein aggregation Effects 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000005185 salting out Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000002415 sodium dodecyl sulfate polyacrylamide gel electrophoresis Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000006557 surface reaction Methods 0.000 description 1
- 238000005199 ultracentrifugation Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N2021/6417—Spectrofluorimetric devices
Abstract
A method for measuring the solubility of protein comprises the following steps: passing the solvent through a 0.22 mu m filter membrane; after the total protein concentration is more than 2.0 g/L, the liquid or solid is dissolved to the total concentration of more than 2.0 g/L, the solution is diluted to below 0.2 g/L in a gradient way to obtain the total protein concentrationC iThe sample series of (1); emitting signals in the vertical direction of the exciting light and at the same wavelength of the exciting light are resonance scattering signals RLS; (ii) the RLS signal of the sample is determined to beY iAnd determining the mean value and standard deviation SD of the RLS signal of the solvent; linearly fitting data with the relative solvent RLS signal increment not more than 5 times of SD to obtain a first-stage linear model, linearly fitting data with the relative solvent RLS signal increment more than 6 times of SD and increasing with the protein concentration nearly linearly to obtain a middle-stage linear model, wherein the intersection point of the two linear models is a protein solubility approximate value; the RLS emission is scanned between 350nm and 450 nm for samples of the same concentration of protein, and the higher the RLS signal the lower the solubility of the protein in the sample or the insoluble particles contained in the sample, within the detectable range of the instrument.
Description
Technical Field
The invention relates to a protein solubility measuring technology, in particular to a technology for measuring the solubility of protein in a solvent based on resonance light scattering, which is suitable for quantitatively comparing the solubility of different proteins and qualitatively comparing the quality of different batches of samples of the same protein.
Background
Water-soluble proteins have important applications. The higher the protein solubility, the lower the recombinant expression production cost; the protein preparation injected into the body for treatment or targeted development has higher solubility and higher application safety. Increasing protein solubility is one of the tasks of protein molecular engineering. Therefore, methods for quantitatively determining protein solubility are of great value.
Protein biochemical activity relies on its multi-site contact interaction with other components and is therefore sensitive to steric hindrance near its active site. The smallest protein structure with complete biochemical function is called a protein structural unit; proteins require that the structural units be maintained in a dispersed state, also referred to as a solubilized state, for maximum biochemical activity. If the protein structural unit is aggregated, the biochemical activity of the protein structural unit is reduced, and the sedimentation speed is increased; protein aggregates correspond to the protein aggregation state. In aqueous solution, the maximum total protein concentration at which the aggregation state of the protein structural unit is negligible is the protein solubility. The aggregation state and the dissolution state of protein structural units in aqueous solution are in dynamic equilibrium and are influenced by various factors. The equilibrium of the aggregation state and the dissolution state of the protein structural unit is not interfered, and the protein solubility is obtained by measuring the concentration of the dissolution state after the aggregation state is completely removed; such separation assays require suitable separation techniques including centrifugation, filtration and a combination of salting out. The aggregation state of the protein structural unit is faster than the settlement of the dissolved state, and the high/ultra-high speed centrifugation can remove the aggregation state of the protein structural unit; the high/ultracentrifugation completely separates the aggregation state of the protein structural unit with a long time and a high centrifugal force, the dissolved state of the protein structural unit is also settled during the centrifugation and the equilibrium of the dissolved state and the aggregation state is disturbed, especially the analysis process is time-consuming. The aggregation state of the structural unit of the filter separation protein usually influences the dynamic balance of the two states, and the non-specific adsorption of the filter material to the protein influences the measurement result. Therefore, new methods are needed to determine protein solubility.
The method for directly and highly sensitively determining the aggregation state content of the protein structural unit without separation is established, so that the protein solubility is directly measured without separation, the interference on the balance between the aggregation state and the dissolution state of the protein structural unit is avoided, the concentration of the protein in the dissolution state is not interfered, and particularly, the analysis efficiency is high. Water-soluble proteins are often spherical and the protein structural units in the solubilized state are also called protein particles. The particle size of the protein structural unit is definitely increased after aggregation. Detection techniques that are sensitive to both particle size and concentration of the particles are suitable for measuring the aggregation state content of the protein structural units, and establishment of such techniques is expected to be useful for direct determination of protein solubility without separation. Resonance Light scattering resonance-Light-scattering (RLS) has been established for nearly 30 years for the measurement of emission signals at wavelengths equal to but perpendicular to incident Light (Heirwegh KP, et al, Selective absorption and scattering of Light by solutions of macromolecules and by particulate subsystems, J Biochem Biophys Methods 1987;14(6): 303) 322). RLS is very sensitive to both particle size and concentration (chemical Z et al, response light scattering technology used for biochemical and pharmaceutical analysis, analytical Chim Acta, 500(1-2): 105. sub.117; Turzhisky V, et al, Spectroscopy of scattered light for the chromatography of micro and nano objects in biology and medicine, applied Spectrosc 2014;68(2): 133. sub.154). The high-concentration protein sample is subjected to gradient dilution to obtain a series of protein samples, and the response of an RLS signal which can be reliably measured to the total concentration of the protein in the sample is analyzed, so that the upper limit of the dissolved state concentration of the protein structural unit, namely the solubility of the protein in the solvent, with negligible content of the aggregation state can be determined.
The RLS signal of the particles can be measured by a dedicated optical detection device in which the incident light is perpendicular to the path of the emitted light, or by a fluorescence spectrophotometer. The diameter of the water-soluble globular protein structural unit is usually 4 to 5nm, and the larger the structural unit contained in the aggregated state, the larger the particle size of the obtained particle. Scanning RLS emission spectrum of serial samples obtained by gradient dilution of high-concentration protein samples can find out measuring wavelength which is sensitive enough to the change of particle concentration in the samples. Liquid or dry powder products of high purity proteins require sterility; the recombinant protein is purified by column chromatography, and the particle size of the packing of the column chromatography is usually below 0.5 mm. Microporous membrane filtration is an important method for ensuring the activity of protein and removing particles which may pollute bacteria and the like. The sterilization effect of the protein product is also required for the quality guarantee of the protein product. If the protein product filtration sterilization operation is not effective, various particles can be brought in the sample, and the RLS signal of the sample can be obviously enhanced. Therefore, RLS reflects the combined effect of insoluble protein and non-protein particles; comparing RLS spectra of different batches of the same protein at the same concentration, or different proteins at the same concentration, is also suitable for qualitative comparison of protein solubility.
However, the RLS technique has not been used to date for determining protein solubility. The possible reasons are that the aggregation state types of high-concentration protein structural units in a solvent are various, the response curve slopes of the measured RLS signals to the concentration of different aggregation states are different due to different particle sizes of different aggregation states, experiments can only measure the total RLS signals of particles in different aggregation states, an obvious covariance effect exists during curve fitting, and the solubility of the protein is determined by analyzing data by using a simple and practical mathematical model. Also, errors in experimental measurements can interfere with the analysis of the resulting RLS signal. Therefore, a simplified method of analyzing the RLS signal versus total protein concentration response curve of a protein sample is needed to determine the maximum protein concentration, i.e., solubility, at which the protein building block is substantially free of aggregation under the assay conditions.
Polynomial fitting is a common curve fitting method. Bovine serum albumin BSA freeze-dried powder and recombinant streptavidin SAV freeze-dried powder are common protein products, and the solubility of the protein products is an index of product performance. Preliminary determination of RLS signal of serial samples after gradient dilution of BSA concentrated solution revealed that RLS signal increased significantly between 350nm and 550 nm after protein concentration exceeded 10.0 g/L (FIG. 1); measurement of the RLS signal at 405 nm revealed that the RLS signal started to rise after BSA concentrations exceeded 5.0 g/L at pH 7.4, but the polynomial did not give a good enough fit (FIG. 2). The RLS emission spectrum after SAV at final concentrations above 2.0 g/L was similar to that of 10g/L BSA (FIG. 3), and the RLS signal rose sharply after SAV concentrations above 1.0 g/L, but the polynomial did not give a good enough fit (FIG. 4). Therefore, a special approximation method is required to analyze the response of the RLS signal to determine protein solubility.
The mean and standard deviation SD of the solvent RLS signal are easy to determine. Selecting RLS data corresponding to a low-concentration protein sample which does not exceed 5 times SD of change of solvent RLS as initial data, and establishing an initial data prediction model by linear fitting; selecting the data with the protein concentration larger than the maximum protein concentration in the initial data sample and the nearly linear response of the RLS signal to the protein concentration as the middle and end data, and establishing a middle and end data prediction model by linear fitting; and the intersection point is suitable for being used as an approximate value of the solubility of the protein sample. Using this approximation, it was found that BSA solubility exceeded 5.0 g/L at pH 7.4 (FIG. 5) and SAV solubility approached 0.8 g/L (FIG. 6). Alkaline protein solubility is generally low (Kramer R M, et al, heated a molecular understating of protein solubility: amplified negative surface reactions with amplified solubility. Biophys J, 2012; 102(8): 1907-. The isoelectric point of the pichia guilliermondii uricase MGU is close to 9.0; the uricase of the pichia guilliermondii is recombined, expressed and purified according to the literature (the cloning, the recombined expression and the characterization of the uricase gene of the pichia guilliermondii, and the like. China journal of bioengineering, 2017, 37(11): 74-82); the method of the invention finds that RLS signals are obviously increased after recombinant expression MGU is 0.24g/L, and the peak wavelength of the signals is close to that of BSA and SAV (figure 7); following the 405 nm RLS signal, the fifth order polynomial was also not able to effectively fit the RLS signal versus protein concentration response curve of MGU (fig. 8), whereas the solubility of MGU was found to be about 0.25 g/L using the approximation method of the present invention (fig. 9).
Qualitatively comparing the solubility of different batches of SAV by using the method; RLS emission spectra were scanned at 1.0 g/L for total protein concentration. The results found that different batches of SAV provided by the same manufacturer had significant differences in RLS emission spectra (fig. 10); the RLS signal increased significantly between 350 and 550 nm at 1.0 g/L for a batch of SAV samples, which may contain particulate impurities, i.e., failed filtration, reduced solubility due to protein denaturation, or insoluble impurities, and which are rejected batches.
Therefore, the intersection point of the first-stage data prediction model and the middle-stage data prediction model can be used as an approximate value of the total protein concentration upper limit and the protein solubility of the protein RLS signal to the particle-free protein concentration response curve, and the method can be a practical method.
Disclosure of Invention
A method for determining the solubility of a protein, characterized by measuring the solubility of a protein of interest by:
step one, solvent pretreatment: using buffer solution or water as solvent, filtering with 0.22 μm microporous membrane to remove particles;
second oneStep, sample gradient dilution: the protein concentration refers to the theoretical concentration or total concentration of the protein in total dissolution; directly carrying out gradient dilution on a liquid protein sample with the concentration of more than 2.0 g/L by using a selected solvent, and dissolving a dry powder or solid protein sample to more than 2.0 g/L by using the selected solvent and then carrying out gradient dilution; protein concentration of the obtained sample seriesC iExpressed, and numbered as i according to the sequence of protein concentration from low to high, wherein i is an integer, the initial value is 1, and the maximum is the number n of samples; the highest protein concentration in the protein sample series obtained by gradient dilution>2.0 g/L, minimum protein concentration<0.2 g/L and no visually observable particles in the sample;
thirdly, resonance scattering signal measurement: an emission signal which is the same as the excitation wavelength in the direction perpendicular to the excitation light or in the direction with an included angle of more than 75 degrees and less than 105 degrees with the excitation light is called a resonance scattering signal and is expressed by RLS; measuring RLS signals by using special optical detection equipment with excitation and emission light paths meeting the requirements or by using a fluorescence spectrophotometer for measuring synchronous fluorescence;
and fourthly, selecting the measuring wavelength of the RLS signal: scanning a protein sample synchronous fluorescence spectrum between 300 nm and 700 nm by using a fluorescence spectrophotometer; for the highest concentration sample and the second lowest concentration sample with the concentration reduced by more than 10 percent, which have the emission signals not out of bounds in the RLS spectrum, deducting the emission spectrum signals of the samples and the RLS spectrum of the solvent to obtain a protein net RLS signal; selecting any wavelength between 390 and 415nm or the wavelength with the highest net RLS signal of the protein sample in the wavelength interval as the measurement wavelength lambda of the protein RLS signal;
step five, measuring the signal of the solvent RLS: independently sampling the solvent at the selected determination wavelength lambda, and repeatedly determining the RLS signal of the solvent for not less than 5 times to obtain the mean value mean and standard deviation SD of the RLS signal of the solvent;
sixthly, response curve determination: determining RLS signal for each protein sample asY i(ii) a Wherein the content of the first and second substances,Y ithe index i corresponds to the sample number, i.e. to the protein concentration of the sampleC iCorresponding; for analysisY iAre all within the signal intensity range which can be accurately measured by the instrument;
seventh, response curve initial segment dataAnd (3) analysis: from the lowest concentration sampleY iStarting from the beginning until the corresponding sample is obtainedY iThe data from which the mean is subtracted is just not less than 5 times of SD or equal to 5 times of SD, which is called initial segment data; fitting the initial segment data by using a linear function to obtain a prediction model, which is called an initial segment linear prediction model;
and eighth, analyzing the data of the tail section in the response curve: from the sample the protein concentration is greater than the maximum protein concentration covered by the initial data and the result isY iThe difference obtained by subtracting mean is not less than 6 times of SDY iData until the difference after mean subtraction approaches the upper limit of linear increase as the protein concentration in the sample increases, referred to as middle-end data; fitting the middle and end segment data by using a linear function to obtain a prediction model, which is called a middle and end segment linear prediction model;
ninth, protein solubility estimation: and extending the initial linear prediction model and the middle and final linear prediction models, wherein the intersection point is the solubility.
Further, a method for determining the solubility of a protein, which is used for qualitatively comparing the solubility of a protein, scanning an RLS spectrum of the protein at a concentration of 30% above or below the solubility of the protein, and comparing signals between 350nm and 450 nm; in this wavelength range, the higher the RLS signal for a protein sample of the same concentration, the lower the solubility of the protein in the sample or the presence of insoluble particles. The method is suitable for qualitative judgment and quality control by comparing the solubility of protein products, and qualitatively comparing the solubility of different proteins.
Drawings
FIG. 1 RLS emission Spectrum of BSA
Legends 1: BSA, 10g/L, 2: BSA, 2.5 g/L; 3 buffer solution
FIG. 2 response of polynomial fitting of BSA to concentration at 405 nm
FIG. 3 RLS emission spectra of SAV
The legends are 1: SAV, 3.0 g/L and 2: SAV, 1.5 g/L; 3 buffer solution
FIG. 4 response curve of SAV to RLS signal at 405 nm versus concentration
FIG. 5 analysis of RLS Signal versus concentration response curves for BSA at 405 nm by the method of the present invention to estimate solubility
FIG. 6 analysis of RLS signal versus concentration response curve for SAV at 405 nm to estimate solubility by the method of the present invention
FIG. 7 RLS emission spectra of MGU
The legend is 1: MGU, 0.26 g/L and 2: MGU, 0.22 g/L; 3 buffer solution
FIG. 8A response curve of a polynomial fit MGU to RLS signal versus concentration at 405 nm
FIG. 9 analysis of MGU response curve to concentration of RLS signal at 405 nm by the method of the present invention to estimate solubility
FIG. 10 comparison of RLS emission spectra at a total SAV concentration of 1.0 g/L for different batches
The legend is 1: 201812 for the sample to be determined and 2: 201812 for the sample to be determined after filtration;
3, qualified batch sample 201608; 4: buffer solution
Detailed Description
The following are the main reagents, materials and necessary equipment used in the application examples.
Bovine serum albumin BSA lyophilized powder was purchased from Solibao, and streptavidin SAV lyophilized powder was purchased from a certain manufacturer in east China. The recombinant expression of the pichia guilliermondii uricase MGU with the 6His label (the clone, the recombinant expression and the characterization of the pichia guilliermondii uricase gene, etc.) is carried out by reference documents, the Chinese bioengineering journal, 2017, 37(11):74-82 is subjected to affinity purification twice by Ni-NTA, and no obvious hybrid protein is detected by SDS-PAGE. RLS signal was measured using a Cary Eclipse fluorescence spectrophotometer.
In all examples, the buffer used was 50 mM HEPES-HCl, pH 7.4; filtration through a 0.22 μm filter.
The following are specific examples:
example 1: scanning the spectrum of the RLS signal from BSA and determining the response curve of the RLS signal at 405 nm to concentration
Firstly, BSA dry powder is prepared into a solution with the concentration of 20 g/L by using a buffer solution, and the solution is evenly mixed by vortex oscillation for 30 s to promote dissolution.
In the second step, a gradient of high concentration BSA sample was diluted to 0.1 g/L with buffer.
Third, scanning simultaneous fluorescence (10 g/L, 2.5 g/L and buffer) at 300 to 700 nm, the results are shown in FIG. 1.
In the fourth step, 405 nm was selected and the RLS signal was measured for a series of BSA samples in response as shown in figure 2.
In the fifth step, the solubility was estimated approximately by the method of the present invention, and the data was analyzed as shown in FIG. 5.
Example 2: scanning the RLS Signal Spectrum of SAV, determining the 405 nm RLS Signal vs. concentration response Curve
Firstly, preparing 12 g/L solution from SAV dry powder by using buffer solution, and uniformly mixing by vortex oscillation for 30 s to promote dissolution.
In the second step, a high concentration SAV sample was diluted in a gradient to 0.1 g/L with buffer.
Third, scanning simultaneous fluorescence (3.0 g/L, 1.5 g/L and buffer) at 300 to 700 nm, the results are shown in FIG. 3.
In the fourth step, 405 nm was selected and the RLS signal was measured for a series of BSA samples and the response is shown in figure 4.
In the fifth step, the solubility was estimated approximately by the method of the present invention, and the data was analyzed as shown in FIG. 6.
Example 3: scanning the RLS Signal Spectrum of MGU and determining the 405 nm RLS Signal vs. concentration response Curve
In the first step, MGU concentrate protein concentration was 2.6 g/L and samples were diluted in a gradient of 0.013 g/L with buffer.
In the second step, simultaneous fluorescence (0.26 g/L, 0.22 g/L and buffer) was scanned at 300 to 700 nm, and the results are shown in FIG. 7.
In the third step, 405 nm was selected and the RLS signal was measured for a series of BSA samples in response as shown in figure 8.
In the fourth step, the solubility was estimated approximately by the method of the present invention, and the data was analyzed as shown in FIG. 9.
Example 4: scanning RLS signal spectra qualitatively comparing solubility of different batches of SAV
Firstly, dissolving the SAV samples of qualified batches and the SAV samples of batches with the determined quality to 1.0 g/L.
In the second step, the SAV sample of the batch of a quality to be determined is filtered through a 0.22 μm filter.
And thirdly, scanning the RLS spectrum of the qualified batch sample before and after filtration of the undetermined batch sample at 300-700 nm (figure 10).
Fourthly, the consistency of the RLS signals of the SAV samples of the undetermined quality batches is higher than that of the RLS signals of the SAV samples of the qualified batches within the range of 350-550 nm; indicating that the SAV sample of the pending lot failed to be soluble.
Finally, the above embodiments are only used to illustrate the technical solution of the present invention and not to limit the same; it will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present invention and it should be understood that the present invention encompasses the full ambit of the claims appended hereto.
Claims (2)
1. A method for measuring the solubility of a protein, characterized by measuring the solubility of a target protein by the following steps:
solvent pretreatment: buffer solution or water is used as solvent, and the buffer solution or water is filtered by a 0.22 um microporous filter membrane to remove particles;
sample gradient dilution: the protein concentration refers to the theoretical concentration or total concentration of the protein in total dissolution; directly carrying out gradient dilution on a liquid protein sample with the concentration of more than 2.0 g/L by using a selected solvent, and dissolving a dry powder or solid protein sample to more than 2.0 g/L by using the selected solvent and then carrying out gradient dilution; protein concentration of the obtained sample seriesC iExpressed, and numbered as i according to the sequence of protein concentration from low to high, wherein i is an integer, the initial value is 1, and the maximum is the number n of samples; the highest protein concentration in the protein sample series obtained by gradient dilution>2.0 g/L, minimum protein concentration<0.2 g/L and no visually observable particles in the sample;
resonance scattering signal measurement: an emission signal which is the same as the excitation wavelength in the direction perpendicular to the excitation light or in the direction with an included angle of more than 75 degrees and less than 105 degrees with the excitation light is called a resonance scattering signal and is expressed by RLS; measuring RLS signals by using special optical detection equipment which meets the requirements on the directions of excitation and emission light paths or by using a fluorescence spectrophotometer capable of measuring synchronous fluorescence;
RLS signal measurement wavelength selection: scanning a protein sample synchronous fluorescence spectrum between 300 nm and 700 nm by using a fluorescence spectrophotometer; for the highest concentration sample and the sample with the concentration reduced by more than 10 percent, the emission spectrum signal of which is not out of bounds in the RLS spectrum is deducted from the RLS spectrum of the solvent to obtain a protein net RLS signal; selecting any wavelength between 390 and 415nm or the wavelength with the highest net RLS signal of the protein sample in the wavelength interval as the measurement wavelength lambda of the protein RLS signal;
solvent RLS signal measurement: independently sampling the solvent at the selected determination wavelength lambda, and repeatedly determining the RLS signal of the solvent for not less than 5 times to obtain the mean value mean and standard deviation SD of the RLS signal of the solvent;
response curve determination: determining RLS signal for each protein sample asY i(ii) a Wherein the content of the first and second substances,Y ithe index i corresponds to the sample number, i.e. to the protein concentration of the sampleC iCorresponding; for analysisY iAre all within the signal intensity range which can be accurately measured by the instrument;
analyzing the initial data of the response curve: from the lowest concentration sampleY iStarting from the beginning until the corresponding sample is obtainedY iThe data from which the mean is subtracted is just not less than 5 times of SD or equal to 5 times of SD, which is called initial segment data; fitting the initial segment data by using a linear function to obtain a prediction model, which is called an initial segment linear prediction model;
analysis of end data in the response curve: from the sample the protein concentration is greater than the maximum protein concentration covered by the initial data and the result isY iThe difference obtained by subtracting mean is not less than 6 times of SDY iData until the difference after mean subtraction approaches the upper limit of linear increase as the protein concentration in the sample increases, referred to as middle-end data; fitting the middle and end segment data by using a linear function to obtain a prediction model, which is called a middle and end segment linear prediction model;
protein solubility estimation: and extending the initial linear prediction model and the middle and final linear prediction models, wherein the intersection point is the solubility.
2. The method according to claim 1, wherein the solubility of a protein is qualitatively compared by scanning RLS spectra at a concentration of the protein about 30% of its solubility to compare signals between 350nm and 450 nm; in this wavelength range, the higher the RLS signal for a protein sample of the same concentration, the lower the solubility of the protein in the sample or the presence of insoluble particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010454423.6A CN113720812A (en) | 2020-05-26 | 2020-05-26 | Method for measuring protein solubility |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010454423.6A CN113720812A (en) | 2020-05-26 | 2020-05-26 | Method for measuring protein solubility |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113720812A true CN113720812A (en) | 2021-11-30 |
Family
ID=78671998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010454423.6A Pending CN113720812A (en) | 2020-05-26 | 2020-05-26 | Method for measuring protein solubility |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113720812A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103149179A (en) * | 2013-01-15 | 2013-06-12 | 华北电力大学（保定） | Method of quantitatively detecting proteins by Co(NH3)6)3+-DNA resonance light scattering |
| CN103764166A (en) * | 2011-06-22 | 2014-04-30 | 通用医疗公司 | Treatment of proteinopathies |
| CN104311650A (en) * | 2014-09-26 | 2015-01-28 | 安徽省农业科学院农产品加工研究所 | Sulfadimethoxypyrimidine artificial antigen and antibody and preparation method and application thereof |
-
2020
- 2020-05-26 CN CN202010454423.6A patent/CN113720812A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103764166A (en) * | 2011-06-22 | 2014-04-30 | 通用医疗公司 | Treatment of proteinopathies |
| CN103149179A (en) * | 2013-01-15 | 2013-06-12 | 华北电力大学（保定） | Method of quantitatively detecting proteins by Co(NH3)6)3+-DNA resonance light scattering |
| CN104311650A (en) * | 2014-09-26 | 2015-01-28 | 安徽省农业科学院农产品加工研究所 | Sulfadimethoxypyrimidine artificial antigen and antibody and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| 孙蓉;吴文标;: "食品中蛋白质检测技术研究进展", 食品科学, no. 23, 15 December 2012 (2012-12-15) * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Mahler et al. | Protein aggregation: pathways, induction factors and analysis | |
| JP2021099359A (en) | Fluidic separation and detection | |
| Carvalho et al. | Variations on fibrinogen-erythrocyte interactions during cell aging | |
| JP6013328B2 (en) | Target particle quantification method | |
| EP2261642A1 (en) | Gel particle measuring apparatus | |
| EP2579020A1 (en) | Gel particle measurement device | |
| Cheubong et al. | Molecularly imprinted polymer nanogel-based fluorescence sensing of pork contamination in halal meat extracts | |
| CN107727633B (en) | Surface-enhanced Raman spectrum detection platform and preparation method and application thereof | |
| CN110927076A (en) | Biological detection device and detection method adopting gold nanopore array chip | |
| EP1096248A3 (en) | Method and apparatus for measuring concentration of a solution | |
| CN114487399A (en) | Method for joint analysis of particle size and surface marker | |
| CN113720812A (en) | Method for measuring protein solubility | |
| CN116235035A (en) | Measured properties of delivery vector samples via isolated viral genes | |
| US20210116448A1 (en) | Method for measuring fibrinogen concentration in blood sample and nanoparticles for same | |
| Rhodes et al. | Determination of size, molecular weight, and presence of subunits | |
| WO2016125243A1 (en) | Exosome assay method and exosome extraction method | |
| Little et al. | Single-label fluorescent derivatization of peptides | |
| CN101639444B (en) | Method for nano particle reinforced fluorescence polarization analysis | |
| Wang et al. | Batch injection analysis using fiber-optic fluorometric detection | |
| US20120295278A1 (en) | Fluorescence detecting method, method for producing fluorescent beads, and fluorescent beads | |
| US20210025827A1 (en) | Methods for determining adjuvanted protein concentration and percent adsorption using intrinsic fluorescence | |
| Krull et al. | Biopolymer determinations by high-performance liquid chromatography with low angle laser light scattering photometry | |
| KR102272031B1 (en) | Method for Raman Spectroscopy Based Protein Quantification, System and Method for Raman Spectroscopy Based Bio-Marker Quantification | |
| US20070117220A1 (en) | Method and apparatus for measuring fluorescence polarization in lab-on-a-chip | |
| JP2006343201A (en) | Protein aggregation prevention agent, protein aggregation prevention method using it, and specimen analysis tool |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |