CN1511846A - Ginkgo protein GAPIIa and its preparing method and use - Google Patents

Abstract

The present invention belongs to the field of plant protein separating and purifying technology, and is ginkgo protein GAP IIa separated from gingko and with functions of delaying senility and resisting oxidation and its preparation process and use. The present invention via the process of salt separation, salt dissolution, two-step ion exchanging chromatography and other steps, new protein GAP IIa of molecular weight 29248 Da is separated from gingko and purified. The primary structure and spatial structure detection shows that GAP IIa consists of two peptide chains, GAP IIa-1 and GAP IIa-2, with similar molecular weight and similar amino acid sequence and connected via disulfide bond and with a few glycosyl via O-glycosidic bond. Each of GAP IIa-1 and GAP IIa-2 contains peptide segments of peptide mass number of 911, 1-11 and 2470. The ginkgo protein may be used in producing health food and medicine for resisting oxidation and delaying senility.

Description

Ginkgo protein GAPIIa and preparation method thereof and purposes

Technical field

The invention belongs to vegetable-protein separating and purifying technology field, relate in particular to from gingko (ginkgo) isolate a kind of have delay senility and oxidation resistant new protein ginkgo protein GAPIIa its Preparation method and use.

Background technology

Ginkgo is Gymnospermae Ginkgopsida ginkgo plant (GinKgo bilba L.), is that a section one belongs to a kind of special plant, claims gingko, Gong Sunshu again, is one of distinctive ancient rare tree of China.The nuclear of ginkgo kind reality is commonly called as gingko, and its kernel is the edible part, because it is nutritious, is taken as top grade that health prolongs life since ancient times, and has modernly become traditional exported product.Main medicinal efficacy for the gas of astringing the lung, relieving asthma and cough, only be with turbid, dwindle just, have that the asthma of treatment, phlegm are coughed, leukorrhea, gonorrhoea, seminal emission, gonorrhoea, a just effect such as frequency.In addition, also make tetter and surgical infections such as treatment nasal surface blackspot, rosacea and cephal and facial eczema tinea.

Modern medicine study prove (Zhou Yuwen. the anti-microbial effect of gingko.Chinese Medical Journal, 1980,36 (12): 549-550), gingko all has in various degree restraining effect to polytype staphylococcus, suis, diphtheria corynebacterium, anthrax bacillus, intestinal bacteria, Corynebacterium diphtheriae etc.Carry out pharmacological research and Study on Physiological Activity to gingko for over ten years, the main achievement that obtains at present has:

1. gingko have the obvious suppression growth of bacillus tubercle effect (Li Weipu. anti-microbial effect of oil immersion gingko and poisoning.The Jiangxi Chinese materia medica, 1981,2 (2): 145-146)

2. from gingko isolating hydroxyl phenols have anticancer and anti-microbial effect (Xu Lihua, Zhao Lichang. the pharmaceutical use of gingko is inquired into.The Shandong medicine industry, 1997,16 (4): 47-48)

The effect of 3. anti-ageing, antifatigue, hypoxia tolerance (Zhang Weiming, Zhao Baitao, Wang Hong. ginkgo kernel is to the influence of small white mouse SOD vigor.China's wild plant resource, 1995 (1): 24-26; Wear foundation, Chen Jingheng. the gingko extracting solution is to the influence of small white mouse heart and brain lipofuscin level.Nanjing Medical University's journal, 1994,14 (3): 411-416; Zhao Baitao, Qin Changqing. the nutrition of gingko juice beverage and functional study.China's wild plant resource, 1995 (1): 19-23)

The effect of 4. relievining asthma, eliminating the phlegm (Xu Changhua, Yu Liangdong, Li Bo. the experimental study of gingko consumption in the dingchuan decoction.The Zhejiang Journal of Traditional Chinese Medicine, 1989,24 (3): 123-124)

5. prevent and treat tetter, promote the growth of human epidermal cell, prolong the epidermic cell life-span (Ma Shihong. the application of ginkgo in makeup.China's wild plant resource, 1995 (1): 35-38).

Though gingko has good health care and prophylactic function, is referred to as " priceless treasure ".But the effective constituent research to gingko is also not really deep, is by which composition to be played a major role as for the gingko pharmacologically active, and whether ginkgo protein has important medicinal health function, it be unclear that.Domestic, the research about ginkgo abroad mainly concentrates on the Ginkgo Leaf, and it is few to the proteic research of gingko, only at Hexiang Wang in 2000, the separation from gingko of Tzi Bun Ng report obtains antifungal protein (the Hexiang Wang that molecular weight is 13kDa, Tzi Bun Ng, Ginkbilobin, a Novel AntifungalProtein from Ginkgo biloba Seeds with Sequence Simi larity to Embryo-Abundant Protein.Biochemical and Biophysical Research Communications, 2000.279 (2) .-407-411).

Separation and purification method of protein specific aim is very strong, and various objectives albumen need adopt different, special-purpose methods.At present, ion-exchange chromatography is a most popular chromatographic technique in the protein drug separation and purification process, and many have active protein by the ion exchange chromatography chromatographic separation and purification.Wang Wenzhong etc. (Wang Wenzhong, Pan Kezhen etc. proteic separation purification of twig and leaf of Royal poinciana seed and biochemical property.Journal of biological chemistry, 1995,11 (3): 270-275) utilize DEAE-Sephadex A-25, SephacrylS-200 to separate the twig and leaf of Royal poinciana seed albumen of having purified, think that according to biochemical property it may be a proteolytic ferment with chromatography columns such as DEAE-52 Mierocrystalline celluloses.Li Ming etc. (Li Ming, Chen Zhengyan etc. the research of agkistrodon halys ussuriensis poison nerve growth factor.Snake will, 1997,9 (4): 20-23) adopt ammonium sulfate, DEAE Mierocrystalline cellulose and the separation and purification from agkistrodon halys ussuriensis of CM cellulose ion-exchange chromatography to go out malicious nerve growth factor, can impel the intensive growth of neurocyte projection; (Wang Xiaohui, Wang Huali etc., the research of analgesic composition in the agkistrodon acutus snake venom such as Wang Xiaohui.China's biochemical drug magazine, 2001,22 (4): 198-199) a kind of protein of purification from the agkistrodon acutus snake venom with analgesic activity, can replace opioid drug, also be the DEAE-Sepharose ion exchange chromatography that adopts.

Gel filtration method is not generally used separately, but is used simultaneously with other chromatography methods when the purification activated protein.Wang Runhua etc. (Wang Runhua, Zheng Shuo etc. the purifying of mole cricket element and the preparation of immunotoxin thereof.Journal of biological chemistry, 1998,9 (5): 581-590) adopt gel filtration chromatography to adopt ion exchange chromatography from mole cricket, to be purified into ribosome inactivating protein more earlier.Literary talent skill etc. (literary talent skill, Zhang Yanhong etc. the research of gel-filtration and ion exchange chromatography purifying corn CuZn-SOD.2001,22 (2): also be to adopt Sephadex G-75 to adopt DEAE-32 from corn, to be purified into CuZn-SOD's more earlier 88-92).The most complex process of existing method, extraction yield is low, the easy inactivation of protein in the operating process.

Separation and purification about the gingko activated protein yet there are no report, and existing method also is not suitable for the separation and purification of ginkgo protein.

Summary of the invention

The objective of the invention is to from gingko ((GinKgo bilba L.)) kernel, isolate a kind of protein of the unknown, a kind of separation, purifying, evaluation and this proteic method of preparation are proposed, explore this proteic biological activity and anti-oxidant and delay senility aspect possible purposes.

The invention provides a kind of new biological activity that has, particularly may exist to delay biological decay and oxidation resistant new agnoprotein.This proteic peptide quality fingerprinting spectrum (PMF) is carried out the Peptldent database retrieval, do not found the protein that is complementary with its correlation parameter.(PST) carried out the SWISS-PRO database retrieval to peptide sequence tag, do not find and its homologous sequence, proves that this is to separate the new protein that obtains first.The present invention also provides from gingko separation and purification to obtain this and has delayed senility and anti-oxidant proteic preparation method.The present invention also provides described protein to be used to prepare to delay senility and the possible purposes of anti-oxidant aspect.

The present invention is achieved through the following technical solutions:

A kind of protein that derives from gingko (GinKgo bilba L.) kernel, described albumen is defined as the GAPIIa ginkgo protein, and its accurate molecular weight is 29248 Da.

Defined Protein G APIIa has two two peptide chains that are defined as GAPIIa-1 and GAPIIa-2 that molecular weight is approaching, aminoacid sequence is similar, and they connect to form described protein by disulfide linkage, and connect a spot of glycosyl in O-glycosides key mode; Having peptide total mass number as described below in GAPIIa-1 and GAPIIa-2 jointly is that 2470 peptide section and peptide total mass number are 1911 peptide section, and its accurate molecular weight is respectively 2470.0044 and 1910.9644; Wherein the peptide total mass number be 1910.9644 peptide section sequence as shown in Figure 2, have 17 amino-acid residues; The peptide total mass number be 2470.0044 peptide section sequence as shown in Figure 3, totally 23 amino-acid residues.

The feature of described GAPIIa-1 and GAPIIa-2 has the peptide quality zymogram of using Trypsin lytic enzyme enzymolysis shown in accompanying drawing 5 and accompanying drawing 6 difference; Described GAPIIa-1 and GAPIIa-2 can be hydrolyzed into many peptide sections that differ in size, the peptide total mass number has 8 sections at the GAPIIa-1 more than 900, i.e. the peptide total mass number of hydrolysis is respectively 911.92,1075.82,1912.36,1331.00,1638.09,2471.52,3098.98 and 3495.22; GAPIIa-2 has 5 sections, and corresponding peptide total mass number is 911.87,1844.28,1912.38,2242.56,2471.56; Wherein the peptide total mass number is arranged is that 911 peptide section, peptide total mass number are that 1911 peptide section and peptide total mass number are that 2470 peptide section is mated mutually for two peptide chains, and their molecular weight equates that aminoacid sequence is identical.

The preparation method of ginkgo protein GAPIIa, as described in following steps:

1) from the gingko kernel, extracts the gingko white protein, prepare gingko sphaeroprotein and gingko salting-in-protein simultaneously;

2) anionic cellulose ion exchange chromatography;

3) negatively charged ion dextrane gel ion exchange chromatography;

The preparation method of gingko white protein and sphaeroprotein is as follows:

1) with the gingko spent meal under 4 ℃, solid-liquid ratio adds 0.14mol/L NaCl solution by 1: 3 (w/v), divides three extractions, obtains the molten extracting solution of gingko salt, with the molten extracting solution freeze-drying of gingko salt, obtains the gingko salting-in-protein;

2) the molten extracting solution of gingko salt is centrifugal, obtain supernatant liquor, discard precipitation;

3) with step 2) supernatant liquor that obtains adds powder ammonium sulfate makes the saturation ratio of supernatant liquor reach 35%, separates out foreign protein, and centrifugal; Obtain supernatant liquor, discard precipitation;

4) supernatant liquor that step 3) is obtained adds powder ammonium sulfate makes the saturation ratio of supernatant liquor reach 90%, separates out white protein and sphaeroprotein, and centrifugal; Abandoning supernatant;

5) precipitation that will obtain is dialysed to distilled water, sloughs ammonium sulfate, separates out sphaeroprotein simultaneously; It is centrifugal,

The supernatant liquor that obtains, freeze-drying obtain the gingko white protein; The precipitation that dialysis is separated out is carried out freeze-drying, obtain the gingko sphaeroprotein.

Wherein anionic cellulose ion exchange layer analysis method is as follows:

With the pH value is that 8.0 50mmol/L trolamine buffered soln prepares sample-loading buffer, behind the balance chromatography column, with sample on the ginkgo protein matter solution on the DEAE-Cellulose chromatography column, flow velocity 0.2ml/min.Be eluted to earlier and do not have the peak appearance substantially with the NaCl elutriant of the 0.1mol/L of 50mmol/L trolamine buffered soln (pH 8.0) preparation, using the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH 8.0) preparation again is that 0.2ml/min carries out gradient elution with the flow velocity, uses the Fraction Collector fraction collection through the effusive solution of wash-out.

Negatively charged ion dextrane gel ion exchange layer analysis method wherein is as follows:

The described collection protein soln of claim 6 is dialysed to trolamine-hydrochloride buffer of pH 8.0,50mmol/L, remove part salt, slowly join in the DEAE-Sephadex-A50 chromatography column, make protein be adsorbed to the chromatography column top, use the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH 8.0) preparation to carry out gradient elution again, collect mountain portions with Fraction Collector then, after with dialysis band distill water dialysis being removed freshen, lyophilize is GAPIIa freeze-drying sample.

The purposes of described ginkgo protein GAPIIa wherein is used to anti-oxidant and anti-aging health food or pharmacy aspect.

Accompanying drawing and explanation thereof:

Fig. 1: be schema of the present invention;

Fig. 2: the aminoacid sequence that is 1911 peptide sections;

Fig. 3: the aminoacid sequence that is 2471 peptide sections;

Fig. 4: the molecular weight collection of illustrative plates that is the MALDI-TOF-MS of GAPIIa;

Fig. 5: be GAPIIa-1 trypsin digestion peptide MALDI-TOF-MS;

Fig. 6: be GAPIIa-2 trypsin digestion peptide MALDI-TOF-MS;

Fig. 7: be the separating spectrum of GAP at DEAE-Cellulose;

Fig. 8: be that GAPIIa is at DEAE-Sephadex-A50 column chromatography figure;

Fig. 9: be the purity that conventional polyacrylamide gel electrophoresis is identified GAPIIa;

Figure 10: the purity that is the polyacrylamide SDS-PAGE evaluation GAPIIa of 15% concentration;

Figure 11: the CID that is peptide section (2471) among the GAPIIa;

Figure 12: the CID that is peptide section (1911) among the GAPIIa;

Figure 13: the Raman spectrum that is GAPIIa;

Figure 14: the FTIR collection of illustrative plates that is GAPIIa;

Figure 15: the CD that is GAPIIa;

Figure 16: be the GAPIIa stereoscan photograph;

Figure 17: be the GAPIIa transmission electron microscope photo;

Figure 18: be the fluorescence spectrum of GAPIIa in different solvents;

Figure 19: be GAPIIa (ethylene glycol) ultraviolet differential spectra.

Detailed technical scheme is as described below:

After testing, GAPIIa ginkgo protein of the present invention, molecule are made up of 271 amino acid residues altogether, and they are respectively 37 Asp, 28 Thr, 33 Ser, 25 Glu, 25 Gly, 19 Ala, 8 Cys, 28 Val, 7 Individual Ile, 12 Leu, 8 Tyr, 8 Phe, 8 Lys, 3 His, 5 Arg, 6 Pro, 5 Met and 4 Trp.

GAPIIa is the glycoprotein that contains a small amount of sugar, is to be connected on Ser or the Thr residue in O-glycosides key mode between itself and the sugar .

The peptide quality zymogram of GAPIIa-1 and GAPIIa-2 tryptose hydrolase enzymolysis is seen respectively shown in accompanying drawing 5 and 6.

There is version more than 2 kinds in described GAPHa, is mainly beta sheet or coiled structure, and α-helixstructure content Few.

Two types of Trp residues among the described GAPIIa all exist, and the Trp residue that is exposed to the molecule outside is namely arranged, and the place is also arranged In the Trp of hydrophobic interior residue. Conformation in solution, it is littler affected by acid-base value, but the acidity relative effect is bigger, and to having Its conformation change sensitivity of machine solvent.

The method for preparing described GAPIIa, in such a way:

The technology of a kind of extraction from gingko, separation, purifying ginkgo protein (GAPIIa) is selected colory gingko conduct The material of separation and purification ginkgo protein GAPIIa is with the molten method of sodium chloride salt and ammonium sulfate salting-out process extracting protein; Two step ions are handed over Change binding molecule sieve chromatography column separating purification, obtain that new having delays senility and the albumen of antioxidation activity.

In order to keep the activity of protein, all operations all should be carried out at 0-4 ℃.

In order to keep the activity of protein, avoid irreversible denaturation, adopt ammonium sulfate salting-out process to carry out the protein extracting. For richness The collection target protein simultaneously reduces foreign protein or assorted peptide as far as possible, discards saturation degree and be 35% ammonium sulfate precipitation sediment, keeps Saturation degree is 35% to 90% ammonium sulfate precipitation sediment.

For effective separation albumin and globulin, according to the dissolving characteristics of albumin and globulin, with the ammonium sulfate precipitation sediment Distilled water is dialysed, and dislysate is more centrifugal through 10000r/min, and collects supernatant.

The present invention adopts two step ion-exchange binding molecule sieve chromatography column separating purifications separate targets albumen from albumin. In order to improve Separative efficiency keeps the activity of protein simultaneously, and ionic strength and pH are important parameters wherein. So the first step adopts The DEAE-Cellulose ion-exchange chromatography, the triethanolamine of pH 8.0,50mmol/L-hydrochloride buffer balance chromatographic column is through upper After the sample absorption, carry out wash-out with the method for step-by-step movement and gradient type combination, namely use earlier the NaCl wash-out of 0.1mol/L ion concentration Liquid is eluted to does not have the peak appearance substantially, and the NaCl eluent with the 0.2mol/L-0.4mol/L ion concentration carries out gradient elution again, Collect eluent. Second step adopts the anion-exchange column-DEAE-Sephadex-A50 with ion-exchange and the double performance of molecular sieve Chromatographic column is further purified target protein. In order to have reduced the step of desalination drying, avoid simultaneously protein denaturation, with the first step Separate the albumen eluent that obtains and earlier triethanolamine-hydrochloride buffer of pH 8.0,50mmol/L is dialysed remove portion salt After, slowly join in the DEAE-Sephadex-A50 chromatographic column, make GAPII be adsorbed to the chromatographic column top, use again 0.2mol/L-0.4mol/L the NaCl eluent carry out gradient elution, collect eluent.

In order to preserve better target protein, and keep the activity of protein, the drying means that adopts is vacuum freeze-drying method.

Adopt the GAPIIa sample of above-mentioned technology preparation, purity has reached chromatographically pure and electrophoresis is pure.

Gingko albumin and GAPIIa freeze-dried powder with above-mentioned technology preparation adopt DRI (DR) method (Halliwell B, Gutteridge J MC, Aruoma O I.The deoxyribose method:a simple " test-tube " assay for determination of rate contents for react ions of hydroxyl Radicals.Anal Biochem., 1987,165:215-219) and nitroblue tetrazolium (NBT) photochemical reduction method (go into business it Careful, Yang Xianqiang. the studies on Spectrophotometric Determination of Tea Polyphenols Scavenger of ROS free radical. tealeaves, 1993,19 (1): 25-27) measure Their oxidation resistance, result of study show that ginkgo protein has good removing or suppresses hydroxyl radical free radical and superoxide anion By basic ability, and active in good to suppress ultra-oxygen anion free radical.

Adopt the ginkgo protein of above-mentioned technology preparation to prolong by observations such as external, vivo medicine-feeding zoopery and Life span of Drosophila melanogaster experiments Slow old and feeble ability. Experimental result shows that ginkgo protein has antibiooxidation and the effect that delays body aging, and prompting gingko egg Has in vain preferably the mechanism of action of anti-aging effects and is that to have an antioxidation activity relevant with it.

Embodiment

Embodiment 1: the isolation and purification of ginkgo protein GAPIIa

1. albuminised purification

Under 4 ℃ of temperature, solid-liquid ratio adds 0.14mol/L NaCl solution by 1: 3 (w/v), divides three times with the abundant homogenate of 500g gingko spent meal, and homogenate is centrifugal 15min under the 10000r/min rotating speed.Get supernatant liquor, add solid ammonium sulfate and reach 35 (w/w) % saturation ratio.Stir and place more than the 1h, centrifugal 15min gets supernatant liquor under the 10000r/min rotating speed.Add solid ammonium sulfate again and reach 90 (w/w) % saturation ratio, stir and place more than the 1h, centrifugal 15min under the 10000r/min rotating speed collects crude protein.The crude protein precipitation heavily is dissolved in the distilled water, and the dialysis membrane of using 1.0kDa is to distill water dialysis.Along with the reduction of salt concn, sphaeroprotein can slowly be separated out, with the protein soln centrifugal 15min under the 10000r/min rotating speed that dialysed.Get supernatant liquor, lyophilize gets 18.6g gingko white protein.

2. anionic cellulose ion exchange chromatography

Take by weighing DEAE-Cellulose resin 50g, handle 30min with 0.5mol/L NaOH earlier, suction filtration is washed to pH9, handles 30min with 0.5mol/LHCl then, and distilled water is washed till pH6-7.Handle 30min with 0.5mol/L NaOH more subsequently and make it to transfer to OH ^-Type.And then, make it to transfer to Cl with 5% NaCl eluant solution ^-Type.The DEAE-Cellulose that 50g handles well can load 400 * 30mm post, and the 20-30mm space is stayed in the post upper end, covers with water.

Behind sample-loading buffer (being that the pH value is 8.0 50mmol/L trolamine buffered soln) balance chromatography column, with sample on the ginkgo protein matter solution on the DEAE-Cellulose chromatography column, flow velocity 0.2ml/min.Be eluted to earlier and do not have the peak appearance substantially with the NaCl elutriant of the 0.1mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation, using the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation again is that 0.2ml/min carries out gradient elution with the flow velocity, through the effusive solution of wash-out, the volume of collection is the 4ml/ pipe with the Fraction Collector fraction collection.Mierocrystalline cellulose anion-exchange chromatography figure sees accompanying drawing (7).

3. negatively charged ion dextrane gel ion exchange chromatography

Take by weighing 10g DEAE-Sephadex-A50 dried resin, with 50mmol/L trolamine buffered soln (the pH value is 8.0) swelling 1h in boiling water bath.With 1.0mol/L NaOH the outstanding pH that starches of resin is transferred to 8.0, leave standstill, allow resin avale, remove supernatant liquor.With trolamine buffered soln washing about three times, be 8.0 and remain unchanged until pH.10g handles DEAE-Sephadex-A50 well can load 400 * 30mm post.

The protein soln of collecting is dialysed to trolamine-hydrochloride buffer of pH8.0,50mmol/L, remove part salt, slowly join in the DEAE-Sephadex-A50 chromatography column, make protein be adsorbed to the chromatography column top, use the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation to carry out gradient elution again, collect mountain portions with Fraction Collector then, called after GAPIIa.Dextrane gel ion exchange chromatography figure sees accompanying drawing (8).The GAPIIa salts solution of collecting, with the dialysis band distill water dialysis is removed freshen after, lyophilize is GAPIIa freeze-drying sample.

From 500g degreasing gingko powder, can make 15mg purifying GAPIIa approximately.

Embodiment 2: the evaluation of ginkgo protein GAPIIa

1.DEAE-Sephadex-A50 the purity of GAPIIa is identified

The GAPIIa sample that purifying in the embodiment (1) is obtained carries out a DEAE-Sephadex-A50 column chromatography (as accompanying drawing (8)) again.From accompanying drawing as can be seen, has only a single symmetrical peak.Therefore, can think that GAPIIa is a homogeneous at chromatography in nature, its purity reaches chromatographically pure.

2. the purity of routine-polyacrylamide gel electrophoresis and SDS-PAGE GAPIIa is identified

Adopt conventional polyacrylamide gel electrophoresis the most frequently used and that have a high-resolution to identify the purity of GAPIIa.GAPIIa is made into the solution that concentration is 2mg/mL, is that 20uL carries out point sample by sample size, electrophoresis 6h under 100V voltage stabilizing condition.(Virahol: acetate: fixing 1h water=25: 10: 65), again with Kao Mashi light blue R-250 dyeing 4h, decolouring with 7% acetic acid solution does not at last extremely have background substantially with stationary liquid earlier for gel behind the electrophoresis.Can see being a protein band from accompanying drawing (9), therefore can identify that the GAPIIa sample is that electrophoresis is pure.

Adopt SDS-PAGE identification of protein purity, can reflect the situation of subunit that protein contains.Protein treatment solution preparation: take by weighing Tris 0.665g, glycerine 5.5mL, mercaptoethanol 2.5mL, 5gSDS is water-soluble, and transferring pH with HCl is 8.0, adds tetrabromophenol sulfonphthalein 20mg and dissolves the back water fully and be settled to 50mL.

Separation gel pH of buffer 8.8 concentrates glue pH of buffer 6.8; Electrode buffer pH8.3; Resolving gel concentration 15%; Concentrate gum concentration 4%; Sample and standard specimen all are made into the solution that concentration is 2mg/mL with the protein treatment solution, and heat 3-5min in boiling water, are cooled to room temperature and make point sample usefulness; Sample size 20uL; 100V voltage stabilizing electrophoresis 6h.With needing through 100 ℃ of heat treated behind the sample buffer preparation sample.Dissociating buffer, concentrated damping fluid, electrode buffer and sample solution all contain SDS.(Virahol: acetate: fixing 1h water=25: 10: 65), again with Kao Mashi light blue R-250 dyeing 4h, decolouring with 7% acetic acid solution does not at last extremely have background substantially with stationary liquid earlier for gel behind the electrophoresis.Accompanying drawing 10 is a purity of identifying GAPIIa with the polyacrylamide of 15% concentration, at two protein bands of 14.4KDa place appearance, shows that GAPIIa is is that peptide chain about 14.4KDa is with the protein of disulfide-bonded by two molecular weight among the figure.

3.MALDI-TOF-MS measure proteic molecular weight and peptide quality fingerprinting collection of illustrative plates

3.1 GAPIIa molecular weight determination

Adopting the MALDI-TOF-MS mensuration GAPIIa molecular weight of Tianjin, the island Kompact SEQ of Kratos company type is 29247Da.Surveying periodic instrument condition is nitrogen laser, wavelength 337nm, linear flying distance 1.2m, acceleration voltage 20kV, detector voltage 25kV.Matrix is α-Cyano, gets an amount of α-Cyano in plastic centrifuge tube, adds 0.1%TFA/50% acetonitrile solution 40～100 μ L, and fully the vibration back is centrifugal, makes the centrifuge tube bottom have a little solid α-Cyano to be advisable, and gets the supernatant saturated solution and uses.The equal water preparation of interior external standard.GAPIIa is dissolved in the deionized water, is made into 40pmol μ l ^-1Solution, get 1 μ L then and mix some target in back with the saturated matrix solution of equal-volume and measure, just carrying out interior calibration with CytoC (10pmol).Mass spectrum such as accompanying drawing (4).

3.2 the mensuration of GAPIIa peptide quality fingerprinting collection of illustrative plates

Adopt of two the peptide chain separation and purification of SDS-PAGE electrophoretic method with GAPIIa.Prepare 12.5% separation gel, 3.3% concentrates glue (the SDS-PAGE glue of 20cm * 20cm * 0.1cm), glue on the vertical slab electrophoresis instrument.After treating that glue solidifies, last sample carries out electrophoresis, and constant current 48mA arrives the sheet glass bottom until the tetrabromophenol sulfonphthalein forward position.Coomassie brilliant blue G250 dyeing 2h, decolouring is spent the night.

After will separating from electrophoresis,, downcut along protein band dyeing edge, be cut into 1mm with blade through two protein bands of coomassie brilliant blue staining ²Blob of viscose, place the Eppendorf pipe respectively, wash 2-3 time with 100 μ l, 50% acetonitrile/100mM bicarbonate of ammonia, each 20 minutes are clean to decolouring.Film after the decolouring places vacuum drier SpeedVac (Savant Instruments, Holbrook, NY, USA) drying is 20 minutes in, (25mM ammonium bicarbonate soln, pH8.0) 5-10 μ l place 4 ℃ of refrigerators to place 40min and make film absorb enzyme liquid fully to add the trypsin solution of 10ng/ μ L then, add 10 μ L 25mM ammonium bicarbonate buffers again, be incubated overnight in 37 ℃.Extract enzyme with 5%TFA 50-100 μ L in 40 ℃ and cut peptide section 1h once, 50%ACN/2.5%TFA solution with equal volume extracts 1h once in 30 ℃ again, use 50 μ L ACN supersound extraction at last once, merge No. 3 times extracting solution, carry out drying with vacuum drier SpeedVac.Dried sample supplies mass spectroscopy with the TFA solution dissolving of 3-5 μ L 0.5%.Interior mark: Regular Insulin, external standard: Regular Insulin oxidation B chain.Above solution 0.6 μ l is used for MALDI-TOF-MS and analyzes.For the sample of manual order-checking, need use C ₁₈Ziptip (Millipore, Bedford, MA, USA) desalination.The desalination step is operated to specifications.Sample after the desalination places the needle of metallizing palladium to measure, and the peptide quality fingerprinting collection of illustrative plates that obtains two peptide chains of GAPIIa is seen accompanying drawing (5) and (6) respectively.

4.ESI-MS/MS measure the GAPIIa partial sequence

The solution of getting the above preparation of 0.6 μ l is used for ESI-MS/MS assay determination GAPIIa partial sequence.The collection of illustrative plates of analyzing is seen accompanying drawing (11) and (12), the results are shown in Table (1).

Table 1 peptide total mass number is the aminoacid sequence of 2470.0044 and 1910.9644 peptide section

The total mass number Theoretical Mass that experiment records is counted the aminoacid sequence of error (Da) theoretical error peptide section

(％)

2470.0044 2472.681 -2.6766 0.0893 AVVVDSNTGETHWCGEGMPDPNR

1910.9644 1913.171 -2.2066 0.1155 LVGNTADLGNWQSMHLR

ESI-Q-TOF-MS/MS is that the quadrature of Britain Micromass company quickens esi-msn instrument Q-TOF2.Be equipped with capillary liquid chromatography and receive the spraying source that rises.All mensuration are all carried out under the positive ion mode.Mass spectrometric correction is gauged with the tandem mass spectrum fragment of Glu-fib, and mass accuracy is less than 0.1Da.Atomization gas is a nitrogen, and collision gas is an argon gas.80 ℃ of source temperature are about taper hole voltage 50V.The TOF acceleration voltage is 9.1Kv.The MCP detector voltage is 2.2Kv.When carrying out the nano-ESI-MS/MS analysis, capillary voltage is 800-1000V, and the size of regulating collision energy and collision gas makes and obtains a good tandem mass spectrum figure.This mass spectrum goes out peptide section sequence by the special software MasSeq direct derivation of Micromass after the special software MaxEnt3 of Micromass handles.(Protana, Odense Denmark) are disposable special-purpose needle to the borosilicate electron spray(ES) pin of metallizing palladium (palladium-coated borosilicateelectrospray needle).

5. protein sequence database retrieval

Protein database search program on the internet usage: the Peptldent that Ex PASy Molecular Biology Server website provides ( Http:// www.expasy.ch/tools/peptident.html) and UCSFMass SpcctrometryThe MS Fit that the Facility website provides ( Http:// prospector.ucsf.edu/ht Mlucsf3.0/msfit.ht, peptide quality fingerprinting collection of illustrative plates and peptide sequence tag are carried out the protein data library searching, prove that GAPIIa is an agnoprotein matter.

6. the mode of connection of GAPIIa glycopeptide chain is determined in β-elimination reaction

Adopt diluted alkaline hydrolysis (β-elimination reaction) method of the O-glycosides key of Zhang Weijie, (Zhang Weijie, saccharide complex Biochemical Research technology.Zhejiang, press of Zhejiang University, 1999, second edition: 129) determine the mode of connection of GAPIIa glycopeptide chain.Under nitrogen protection, 30mg GAPIIa is dissolved in 3mL 0.2mol/L NaOH-1.0mol/L NaBH ₄Solution in 40 ℃ of reaction 24h, is neutralized to pH7.0 with 1mol/L acetate in ice bath.Under nitrogen protection,, measure aminoacids content with automatic analyzer for amino acids with 6mol/L HCl hydrolysis.The variation that table (2) is formed for amino acid before and after the reaction, by measurement result as can be known, Threonine and Serine have reduced 1.01% and 1.24% respectively, and L-Ala has increased by 0.64%.According to the variation of these amino-acid residues, can determine to link in O-glycosides key mode between GAPIIa and the glycosyl.

The variation that amino acid is formed before and after table 2. β-elimination reaction

After reacting before the preceding reaction of the amino acid reaction back amino acid reaction

Asp 14.82 13.99 Leu 5.27 4.99

Thr 9.76 8.75 Tyr 4.41 4.70

Ser 9.88 8.64 Phe 4.32 4.95

Glu 11.28 10.38 Lys 4.04 4.23

Gly 4.96 5.96 His 1.63 1.63

Ala 4.71 5.35 Arg 2.79 3.00

Cys 2.97 2.02 Pro 2.13 3.95

Val 9.47 11.28 Met 2.36 2.09

Ile 2.68 2.10 Trp 2.51 1.95

7.GAPIIa Raman spectrum analysis

A small amount of (about 0.1mg) natural GAPIIa lyophilized powder is carried out the Raman spectrum test on the MKI-1000 laser Raman spectrometer, by microcomputer interlock control.The wide 400um of double monochromator slit, sweep velocity is 1cm ^-1/ S.LASER Light Source is the INNOVA 70 type ammonium ion laser apparatus of Coherent company, excitation wavelength 514.5nm, power 250mW.Experiment is 90 ° of direction scattering geometry devices.To the Raman scattering signal scanning of natural GAPIIa lyophilized powder 2 times, make the signal progressive mean and the output of drawing by computer, obtain the Raman spectrogram of natural GAPIIa lyophilized powder, see accompanying drawing (13).

8.GAPIIa Infrared spectroscopy

Compressing tablet behind (about 0.5mg) natural GAPIIa lyophilized powder sample and the Potassium Bromide mixed grinding is measured with the Nicoler-SX-170 Fourier transformation infrared spectrometer on a small quantity, and infrared spectrogram is seen accompanying drawing (14).

9.GAPIIa molecule garden two stratographic analyses

The solution that GAPIIa is mixed with 0.1-0.3mg/mL concentration is tested on two chromatographic instruments of JASCO-500 type garden.Test condition is: sensitivity 2 milli degree; The thick 0.1cm in pond; 20 ℃ of temperature; Sweep limit 180-350nm; Sweep velocity 100nm/min.Garden two color atlass are seen accompanying drawing (15).

10.GAPIIa the scanning electron microscope of state of aggregation and transmission electron microscope observing

After will a small amount of (about 0.1mg) natural GAPIIa lyophilized powder sample putting into the vacuum evaporating instrument and plating the layer of metal film, on the X-650 of Hitachi type scanning electron microscope, observe.The Electronic Speculum condition is: high pressure 20kV, line 5 * 10 ^-9MA, operating distance 15mm.Stereoscan photograph is seen accompanying drawing (16).

A small amount of (about 0.1mg) natural GAPIIa lyophilized powder sample is put into ethanol solution, after carrying with copper mesh, send in the lens barrel of JEM-100CX-II type transmission electron microscope and observe.The Electronic Speculum condition is: acceleration voltage 80kV.Transmission electron microscope photo is seen accompanying drawing (17).

11.GAPIIa endogenous fluorescent characteristics

All fluorescence experiments are all carried out on Hitachi-850 fluorescence spectrophotometry instrument, and 25 ℃ of sample determination temperature excite with the emmission spectrum spectrum width and are respectively 4nm and 2nm.Except that specified otherwise, GAPIIa concentration 0.05mg/mL measures fluorescence spectrum, and solution system is a 0.01mol/L Tris-HCl buffer system (pH7.6).

Except that indicating, excitation wavelength is 282nm, the general fluorescence spectrum of protein under this excitation wavelength about 97% provided by the Trp residue, and Trp is comparatively responsive to polarity of solvent, and therefore available 282nm is the microenvironment of Trp residue among the excitation wavelength research GAPIIa.

Change GAPIIa emission λ max and the fluorescence intensity of pH value (the control group aqueous solution) mensuration when excitation wavelength is 282nm of GAPIIa solution with hydrochloric acid and sodium hydroxide.In one group of hydrochloric acid and sodium hydroxide solution, make their pH values be respectively 2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0, the research potential of hydrogen is to the influence of the endogenous fluorescence spectrum of GAPIIa, and the fluorescence spectrum result of variations sees Table (3).

GAPIIa fluorescence intensity during table 3 different pH values

pH 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Relative intensity of fluorescence 79 80 80.6 78.6 81.4 84 81.8 82.4 82.8

GAPIIa contains in the solution of organic reagent as 30% methyl-sulphoxide, 30% ethylene glycol, 30% ethanol and 30% glycerine at some, observe its emmission spectrum wavelength change, the research organic solvent is to the influence of the endogenous fluorescence spectrum of GAPIIa, and the fluorescence spectrum result of variations is seen accompanying drawing (18).

12.GAPIIa the ultraviolet differential spectra is analyzed

The ultraviolet differential spectra is measured and is carried out with Hitachi's 556 type dual-wavelength double beam spectrophometers, measures the ultraviolet differential spectra of 230-310nm wave band under 25 ℃ of constant temperature.GAPIIa concentration is the aqueous solution of 1mg/mL; The perturbation agent is an ethylene glycol; Glycol concentration is 20% the aqueous solution.GAPIIa ultraviolet differential spectra is seen accompanying drawing (19).

Embodiment 3: the bioactive mensuration of ginkgo protein

1. ginkgo protein is to the scavenging(action) of free radical (OH)

Adopt 2-deoxy-D-ribose (DR) method (Halliwell B, Gutteridge J MC, Aruoma O I.Thedeoxyribose method:a simple " test-tube " assay for determination of rate contents for reactions ofhydroxyl radicals.Anal Biochem., 1987,165:215-219): the KH that in clean rub oral examination tube, adds 0.4mL50mmol/L pH7.5 successively ₂PO ₄-KOH damping fluid, finite concentration sample, 0.1mL 1.04mmol/L EDTA solution, 0.1mL10mmol/L H ₂O ₂, 0.1mL 60mmol/L DR (contrast does not add), 0.1mL 2mmol/L vitamins C, and 0.1mL1mmol/L FeCl ₃, each manages final volume is 1.0mL.37 ℃ of insulations were taken out after 1 hour, added 1mL 25%HCl termination reaction, added 1.0ml 1%TBA solution again, with solution mixing in each test tube, boiled 15min in the boiling water bath, immediately cooling back centrifugal (3000rpm).Survey absorbancy at 532nm wavelength place, and calculate inhibiting rate by following formula:

A wherein ₀, A ₁, A ₂Represent the absorbancy of reference substance and sample blank respectively.Experimental result be the ginkgo protein GAPIIa of 133 μ g/ml to the inhibiting rate of OH up to 69.1%.

2. ginkgo protein is to the scavenging(action) of ultra-oxygen anion free radical

Employing nitroblue tetrazolium(NBT) (NBT) photochemical reduction method (Jia Zhishen, Yang Xianqiang. tea-polyphenol is removed the studies on Spectrophotometric Determination of active oxygen radical. tealeaves, 1993,19 (1): 25-27), improved.Be reflected at 2 20W fluorescent lamps are housed, be lined with all around in the box of aluminium foil and carry out, the conditioned reaction thing is from the distance of lamp, measures with luxmeter that to make it be subjected to light intensity be 4000lx.In the 3ml reaction solution, the concentration that makes riboflavin is 3 * 10 ^-6MolL ^-1, concentration of methionine is 1 * 10 ^-2MolL ^-1Test solution all uses 5 * 10 ^-2MolL ^-1, pH is 7.5 phosphoric acid buffer preparation, under 25 ℃, illumination 20min, riboflavin promptly produce O because of photochmeical reaction ₂ ^-

In above system, add chlorination nitro tetrazole orchid (NBT), make concentration reach 1 * 10 ^-4MolL ^-1, the O that illumination riboflavin produces ₂ ^-NBT can be reduced to blue product, proofread and correct, record its absorbance A, can be expressed as O at the 560nm place with the test solution of unglazed photograph ₂ ^-Content, can remove O after adding scavenging agent ₂ ^-, suppressed the reduction of NBT, recording its absorbancy is A ₁, A-A ₁Expression O ₂ ^-Reduction, then inhibiting rate is:

Experimental result is that the ginkgo protein GAPIIa of 100 μ g/ml is to O ₂ ^-Inhibiting rate up to 60.64%, suitable with the tea-polyphenol of 20 μ g/ml.

3. ginkgo protein antibiont oxidation susceptibility

3.1 ginkgo protein antioxidation in vitro experiment

Every test tube adds 0.20mL 10% liver homogenate, 0.10mL physiological saline or FeSO ₄(5mmol/L) or H ₂O ₂(10mmol/L), the administration group adds the ginkgo protein solution of 0.20mL different concns, and control group adds isopyknic physiological saline, and 37 ℃ of temperature are bathed 1h, puts in the frozen water after the cooling, and the TBA colorimetry is surveyed MDA content.

Every test tube adds 0.20mL 0.50mg/mL mitochondrial protein liquid, the ginkgo protein solution of 0.20mL different concns, and control group adds isopyknic physiological saline, and 37 ℃ of temperature are bathed 24h, put in the frozen water after the cooling TBA colorimetric method for determining rat liver mitochondria MDA content.

Get the 1% rat red blood cell suspension 5.0mL that newly joins, add the ginkgo protein solution of 0.40mL different concns, mixing is put 37 ℃ of temperature and is bathed 24h, puts in the frozen water after the cooling centrifuging and taking supernatant liquor, TBA colorimetric method for determining rat red corpuscle MDA content.

Experimental result shows: spontaneous generation and the Fe of gingko white protein MDA during to the external incubation of liver homogenate ²⁺, H ₂O ₂The generation of bringing out MDA has certain restraining effect, and it is up to 47.55% to the inhibiting rate that MDA generates; The gingko white protein all has significant inhibitory effect to the generation of rat liver mitochondria MDA content, and maximal percentage inhibition is up to 70.97%; The gingko white protein all has the autooxidation of significant inhibition red corpuscle, and maximal percentage inhibition is up to 65.57%.

3.2 anti-oxidant experiment in the body of ginkgo protein

Select the female Kunming of SPF level kind small white mouse for use, and 70 of aged mouses (11-12 monthly age) (45.2 ± 4.3g), 10 (34.2 ± 3.1g) of young mouse (2 monthly age).Aged mouse is divided into 7 groups at random by body weight, 10 every group, promptly aged control group (filling physiological saline), GAP dosage group (100mg/kgd, 50mg/kgd is 25mg/kgd) with GSP dosage group (200mg/kgd, 100mg/kgd, 50mg/kgd), other establishes young control.After each treated animal adaptability is fed a week, irritate stomach and tried thing or contrast, continuous 30 days, sacrificed by decapitation was taken a blood sample then, and taking internal organ is measured.Experimental session is weighed once weekly.

Get each 0.10mL of 10% liver tissue homogenate and serum respectively, press MDA Determination on content method (thiobarbituricacid method) in the test kit liver tissue homogenate, with four oxygen methylpropanes is standard, measures murine liver tissue homogenate and mice serum MDA content at 532nm wavelength place.

Get 5 μ L of 10% liver tissue homogenate and the 12 μ L of 1% liver tissue homogenate respectively, press in the test kit liver tissue homogenate the active measuring method of SOD (hydroxylamine assay) and measure SOD activity in murine liver tissue homogenate and the mice serum.

Get 1% 0.20mL of liver tissue homogenate and hemolysate 0.20mL respectively, press the active measuring method of the GSH-PX of test kit liver tissue homogenate (two sulphur p-nitrobenzoic acid methods) and measure GSH-PX vigor in murine liver tissue homogenate and the mouse whole blood.

Experimental result sees Table (4) (5) and (6) respectively

Table 4. ginkgo protein is to the influence of MDA content in murine liver tissue homogenate and the serum

Group dosage serum liver tissue

(mg/kg·d) (nmol/mL) (nmol/mg?protein)

Aged control 0 9.53 ± 1.25 1.91 ± 0.36

Young control 0 4.32 ± 0.57 0.92 ± 0.16

Gingko white protein 100 7.24 ± 0.54 ^*1.91 ± 0.20

50 7.26±0.61 ^** 1.43±0.30 ^*

25 6.76±0.60 ^** 1.28±0.13 ^**

Gingko salting-in-protein 200 6.51 ± 0.51 ^*1.68 ± 0.40

100 6.40±0.43 ^** 1.45±0.32 ^*

50 5.85±1.20 ^** 1.43±0.29 ^*

^*：P＜0.05， ^**：P＜0.01

Table 5. ginkgo protein is to the active influence of SOD in murine liver tissue homogenate and the serum

Group dosage serum liver tissue

(mg/kg·d) (NU/mL) (NU/mg?protein)

Aged control 0 164.3 ± 15.1 531.1 ± 58.5

Young control 0 291.2 ± 24.7 968.2 ± 84.3

Gingko white protein 100 208.0 ± 10.7 ^*805.8 ± 31.2 ^*

50 216.9±17.5 ^** 604.3±39.9 ^*

25 195.3±10.3 ^** 592.7±56.9

Gingko salting-in-protein 200 208.5 ± 12.8 ^*689.1 ± 65.4 ^*

100 199.6±19.7 ^** 623.0±29.6 ^*

50 203.2±11.5 ^** 611.2±42.9 ^*

^*：P＜0.05， ^**：P＜0.01

Table 6. ginkgo protein is to the active influence of GSH-PX in murine liver tissue homogenate and the serum

Group dosage whole blood hepatic tissue

(mg/kg·d) (NU/mL) (NU/mg?protein)

Aged control 0 63.5 ± 3.2 32.9 ± 3.7

Young control 0 110.4 ± 10.6 50.6 ± 4.8

Gingko white protein 100 91.2 ± 8.7** 39.2 ± 1.9**

50 89.6±9.6** 37.6±3.1**

25 83.4±8.0** 38.0±2.4**

Gingko salting-in-protein 200 87.7 ± 8.4** 42.0 ± 3.7**

100 88.4±5.8** 41.9±3.9**

50 81.4±7.4** 39.7±3.6**

^*：P＜0.05， ^**：P＜0.01

Experimental result shows: the ginkgo protein of feeding all can suppress the generation that laboratory animal is raised MDA in liver tissue homogenate and the serum, and these effect explanation ginkgo proteins can suppress the generation of free radical in the body effectively, and zooblast is played fine provide protection.The ginkgo protein of feeding all can improve the activity of SOD in laboratory animal liver homogenate and the serum, and ginkgo protein can strengthen SOD activity in the body as a kind of antioxidant of trophicity, is the anti-ageing invigorant of ideal.The ginkgo protein of feeding all can improve the activity of GSH-PX in laboratory animal liver homogenate and the serum, illustrates that edible ginkgo protein can swash the in vivo activity of GSH-PX, removes interior free yl effectively, and the protection body is avoided free radical and attacked infringement.

3.3 drosophila survival experiment

Blank substratum and pharmaceutical culture medium preparation: use Semen Maydis powder 34g, sucrose 26g, dried yeast powder 3g, propionic acid 2.0mL, agar 3.0g, distilled water 400mL.Make the blank substratum that does not contain medicine, pharmaceutical culture medium then adds ginkgo protein 3.3mg/100g (low dose group), 10mg/100g (middle dosage group) and 30/100g (high dose group) in basic medium.Get the culture tube of 1.cm * 10cm, collect the fruit bat adult that 10h is hatched, etherization, weighing is divided into 4 groups, and every group of 100 fruit bats are put into 25 fruit bats in every culture tube, and male and female are divided foster, and every pipe is put the 2mL substratum, seals with double gauze.Each organizes fruit bat, and all to put into 25 ± 1 ℃, humidity be 45%～75% incubator, all feed basic medium around preceding, each test group begins to the medicine substratum after 29 days, and every morning 10:00 observes and also writes down dead fly number, changed a subculture in 4 days, observe till the extremely complete death of fruit bat.Write down survival time and the half survival time of every group of fruit bat.Life-span with every group of last dead fruit bat is organized the maximum life span of fruit bat for this.Statistics is respectively organized mean lifetime (algebraic sum of each drosophila survival fate is divided by the fruit bat number in the group) and the maximum life span fate of fruit bat.Draw the drosophila survival curve according to each group fruit bat different time accumulation survival rate.And to each group The average survival time fate employing t check.

Experimental result shows, no matter is male fruit bat or female fruit bat, and middle dosage group (10mg/100g) all can prolong mean lifetime and the average maximum life span of fruit bat.Compare with control group, have utmost point significant difference, the female fruit bat of the rate of on average lengthening the life is 10.87, and male fruit bat is 10.31%.Illustrate that the gingko white protein has the effect that prolongs life span of drosophila melanogaster.

The present invention has following good effect:

The ginkgo protein GAPIIa of purifying of the present invention is a kind of new vegetable protein, and has anti-oxidant and health care that delay senility Function, albumen of the present invention can be used for producing anti-oxidant and health food or pharmacy aspect that delay senility.

Extraction among the present invention, separation, purifying process, but selectivity is fit to the purifying of ginkgo protein GAPIIa, and technological process is short, Be easy to keep the activity of ginkgo protein GAPIIa, GAPIIa purity chromatographically pure and electrophoresis are pure in the sample, can carry out sequence and survey Decide and structural analysis.

Claims (8)

1, a kind of protein that derives from gingko (GinKgo bilba L.) kernel, it is characterized in that: described albumen is defined as the GAPIIa ginkgo protein, and its accurate molecular weight is 29248Da.

2, the albumen of claim 1 definition, it is characterized in that: GAPIIa is by two two peptide chains that are defined as GAPIIa-1 and GAPIIa-2 that molecular weight is approaching, aminoacid sequence is similar, the protein that connects to form by disulfide linkage, and connect a spot of glycosyl in 0-glycosidic link mode; Having peptide total mass number as described below in GAPIIa-1 and GAPIIa-2 jointly is that 2470 peptide section and peptide total mass number are 1911 peptide section, and its accurate molecular weight is respectively 2470.0044 and 1910.9644; Wherein the peptide total mass number be 1910.9644 peptide section sequence as shown in Figure 2, have 17 amino-acid residues; The peptide total mass number be 2470.0044 peptide section sequence as shown in Figure 3, totally 23 amino-acid residues.The peptide total mass number is that 2355 peptide section is that the peptide total mass number is that 1911 peptide Duan Zaiqi C-end connects Thr-Arg-Gly-Lys and forms.

3, described GAPIIa-1 of claim 2 and GAPIIa-2 is characterized in that: the peptide quality zymogram of using Trypsin lytic enzyme enzymolysis is respectively shown in accompanying drawing 5 and accompanying drawing 6; Described GAPIIa-1 and GAPIIa-2 can be hydrolyzed into many peptide sections that differ in size, the peptide total mass number has 8 sections at the GAPIIa-1 more than 900, i.e. the peptide total mass number of hydrolysis is respectively 911.92,1912.36,1075.82,1331.00,1638.09,2471.52,3098.98 and 3495.22; GAPIIa-2 has 5 sections, and corresponding peptide total mass number is 911.87,1844.28,1912.38,2242.56,2471.56; Wherein the peptide total mass number is all arranged is that 911 peptide section, peptide total mass number are that 1911 peptide section and peptide total mass number are that 2470 peptide section is mated mutually for two peptide chains, and their molecular weight equates that aminoacid sequence is identical.

4, realize the preparation method of the described ginkgo protein GAPIIa of claim 1, it is characterized in that:

1) from the gingko kernel, extracts the gingko white protein, prepare gingko sphaeroprotein and gingko salting-in-protein simultaneously;

2) anionic cellulose ion exchange chromatography;

3) negatively charged ion dextrane gel ion exchange chromatography;

5, the described method of claim 4, wherein the preparation method of gingko white protein, sphaeroprotein and salting-in-protein is as follows:

1) with the gingko spent meal under 4 ℃, solid-liquid ratio adds 0.14mol/L NaCl solution by 1: 3 (w/v), divides three extractions, obtains the molten extracting solution of gingko salt, with the molten extracting solution freeze-drying of gingko salt, obtains the gingko salting-in-protein;

2) the molten extracting solution of gingko salt is centrifugal, obtain supernatant liquor, discard precipitation;

3) with step 2) supernatant liquor that obtains adds powder ammonium sulfate makes the saturation ratio of supernatant liquor reach 35%, separates out foreign protein, and centrifugal; Obtain supernatant liquor, discard precipitation;

4) supernatant liquor that step 3) is obtained adds powder ammonium sulfate makes the saturation ratio of supernatant liquor reach 90%, separates out white protein and sphaeroprotein, and centrifugal; Abandoning supernatant;

5) precipitation that will obtain is dialysed to distilled water, sloughs ammonium sulfate, separates out sphaeroprotein simultaneously; Centrifugal, as to obtain supernatant liquor, freeze-drying obtain the gingko white protein; The precipitation that dialysis is separated out is carried out freeze-drying, obtain the gingko sphaeroprotein.

6, the described method of claim 4, the anionic cellulose ion exchange chromatography is as follows:

With the pH value is that 8.0 50mmol/L trolamine buffered soln prepares sample-loading buffer, behind the balance chromatography column, with sample on the ginkgo protein matter solution on the DEAE-Cellulose chromatography column, flow velocity 0.2ml/min.Be eluted to earlier and do not have the peak appearance substantially with the NaCl elutriant of the 0.1mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation, using the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation again is that 0.2ml/min carries out gradient elution with the flow velocity, collects through the effusive solution of wash-out with Fraction Collector.

7, the described method of claim 4, negatively charged ion dextrane gel ion exchange chromatography wherein is as follows:

The described collection protein soln of claim 6 is dialysed to trolamine-hydrochloride buffer of pH8.0,50mmol/L, after removing part salt, slowly join in the DEAE-Sephadex-A50 chromatography column, make protein be adsorbed to the chromatography column top, use the NaCl elutriant of the 0.2mol/L-0.4mol/L of 50mmol/L trolamine buffered soln (pH8.0) preparation to carry out gradient elution again, collect mountain portions with Fraction Collector then, after with dialysis band distill water dialysis being removed freshen, lyophilize is GAPIIa freeze-drying sample.

8, realize the purposes of the described ginkgo protein GAPIIa of claim 1, wherein be used to anti-oxidant and anti-aging health food or pharmacy aspect.

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