CN110655556B

CN110655556B - Preparation and method of immunoregulatory peptide

Info

Publication number: CN110655556B
Application number: CN201911050848.4A
Authority: CN
Inventors: 汪少芸; 杨倩; 蔡茜茜; 陈旭; 田永奇
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-05-18
Anticipated expiration: 2039-10-31
Also published as: CN110655556A; WO2021082294A1

Abstract

The invention provides a method for separating and purifying immunoregulatory peptide by utilizing radix pseudostellariae, which takes radix pseudostellariae as a raw material, and obtains specific immune polypeptide through protein extraction, pepsin and trypsin double-step enzymolysis, separation, purification and freeze drying, wherein the molecular weight of the specific immune polypeptide is 522 Da, and the amino acid complete sequence is as follows: Arg-Gly-Pro-Pro-Pro. The invention eliminates the defects of the immunoregulation medicament, eliminates the public worry about the artificial immunoregulator, and lays a theoretical foundation for developing the food-source-based immune polypeptide and exploring the wide application of the food-source-based immune polypeptide in food and medicine.

Description

Preparation and method of immunoregulatory peptide

Technical Field

The invention relates to a method for separating and purifying immunoregulatory peptide by utilizing radix pseudostellariae, belonging to the technical field of biology.

Background

Immunity is a specific physiological response that occurs when the body is exposed to "antigenic foreign bodies" or "isohexides," the main objective of which is to maintain homeostasis in the body. The immune system responsible for the immune function of the body is a network of cells, tissues and organs that eliminate potentially harmful substances such as bacteria, viruses, fungi, protozoa and prevent the growth of cancer cells. In the living of the body, the immune system serves as the first line of defense against pathogens, providing protection before bodily functions are impaired. However, the immune system is also affected by many factors, including stress, unhealthy lifestyle, pathogens and antigens that can destroy the body's immune system. Therefore, drugs for regulating the immune response of human body have come into play, such as cyclosporine, tacrolimus, glucocorticoid, phytol, aristolochic acid, graphene, levamisole and the like, which have been successfully applied to the regulation of the immune response of human body. However, the toxic side effects and high cost of these drugs limit their use in patients, and most immunomodulatory drugs are not suitable for chronic or prophylactic use. Therefore, the discovery of novel immunologically active peptides from food proteins is an effective therapeutic and prophylactic approach.

Radix pseudostellariae is the root tuber of the pseudostellaria heterophylla of the dianaceae family, also known as the root tuber of the juvenile sea cucumber, namely the juvenile sea cucumber, the root tuber of the pseudostellaria heterophylla, the root tuber of the rice-leaved ginseng and the like, since the beginning of the Qing Dynasty, the herbal of the New Japan, the herbal of the Japan, the Chinese medical works are recorded. The main planting areas of the radix pseudostellariae comprise Fujian, Jiangsu, Shandong, Anhui and the like, wherein the Fujian Cudrania tricuspidata can be planted from the end of Qing dynasty, and is famous at home and abroad and has the reputation of the country of the radix pseudostellariae. So far, researches on chemical components and medicinal effects of radix pseudostellariae are quite extensive, but no relevant reports on preparation of polypeptides by proteolysis of radix pseudostellariae exist.

Therefore, the invention prepares the high-efficiency immune polypeptide with a specific amino acid sequence from the radix pseudostellariae protein zymolyte. The polypeptide can be applied to the industries of food and health care products.

Disclosure of Invention

In order to solve the problems, the invention provides a method for separating and purifying the immunoregulatory peptide by utilizing radix pseudostellariae, and the polypeptide obtained by the method has a specific amino acid sequence.

In order to realize the purpose, the following technical scheme is adopted:

the amino acid sequence of the immunoregulatory peptide is Arg-Gly-Pro-Pro-Pro (RGPPP), and the preparation method comprises the following steps:

(1) extracting the protein of the radix pseudostellariae: grinding radix Pseudostellariae into powder, and extracting radix Pseudostellariae protein by alkali extraction and acid precipitation;

(2) preparation of radix pseudostellariae protein zymolyte: carrying out double-step enzymolysis on the radix pseudostellariae protein by utilizing pepsin and trypsin to obtain a radix pseudostellariae protein zymolyte;

(3) separating and purifying the radix pseudostellariae protein zymolyte: separating and purifying radix Pseudostellariae protein zymolyte by Sephadex G25 chromatography and RP-HPLC reversed-phase high performance liquid chromatography, collecting fraction with highest immunological activity, freeze drying, and identifying amino acid sequence of fraction by Nano LC-MS/MS.

The extraction of the radix pseudostellariae protein in the step (1) is as follows: grinding radix pseudostellariae into powder, adding 0.2-0.3 mol/L sodium hydroxide solution (NaOH) with the corresponding volume according to the mass concentration of 4.0-5.0% of the radix pseudostellariae powder, and leaching for 1.0-3.0 h in a water bath at 50-60 ℃. And centrifuging after leaching, collecting supernatant, adjusting the pH value to 2.5-3.5 by using 1 mol/L hydrochloric acid (HCl), standing for 1-3 h, centrifuging, collecting precipitate, and freeze-drying to obtain the radix pseudostellariae protein.

The preparation of the radix pseudostellariae protein zymolyte in the step (2) is as follows: the method comprises the steps of enabling the concentration of the radix pseudostellariae protein to be 1.0-2.0 w/v%, enabling the pH value to be 1.5-2.5, enabling the temperature to be 30-40 ℃, enabling the enzymolysis time to be 4.0-6.0 h, adding 8.0-10.0 w/w% of pepsin to carry out enzymolysis, adjusting the pH value to be 6.5-7.5 after the reaction is finished, adding 8.0-10.0 w/w% of trypsin, carrying out enzymolysis for 2.0-4.0 h, immediately placing the mixture in a boiling water bath to boil for 10-20 min after the reaction is finished, stopping the reaction, centrifuging the reacted solution, collecting the supernatant, and freeze-drying to obtain the radix pseudostellariae protein enzymolysis product.

The separation and purification of the radix pseudostellariae protein zymolyte in the step (3) specifically comprises the following operations: separating and purifying the radix pseudostellariae protein enzymatic hydrolysate in the step (2), taking deionized water as eluent by sephadex G25, measuring the immunocompetence of the eluent corresponding to each absorption peak by using the sample loading amount of 5mL, the flow rate of 0.3 mL/min and the detection wavelength of 214 nm, collecting the component with the highest immunocompetence, and performing reversed-phase high performance liquid chromatography; performing reverse phase high performance liquid chromatography separation by using an acetonitrile solution with a concentration gradient of 0-55 v/v% and containing trifluoroacetic acid with a volume fraction of 0.05% as an eluent for linear elution, wherein a used chromatographic column is Gemini 5 mu C18, the sample loading amount is 100 mu L, the flow rate is 1 mL/min, the detection wavelength is 214 nm, the immunocompetence of the eluent corresponding to each absorption peak is determined, and the component with the highest immunocompetence is collected and obtained by freeze drying; the amino acid sequences of the fractions were identified using Nano LC-MS/MS. Identifying the amino acid sequences of the components using Nano LC-MS/MS to obtain the amino acid sequence of the immunomodulatory peptide of claim 1: Arg-Gly-Pro-Pro-Pro.

The specific operation of the determination of the immunological activity in the step (3) is as follows: immunological activity to promote mouse splenic lymphocyte proliferation activity in vitroAnd (6) evaluating. The mouse spleen lymphocyte suspension is added into a 96-well plate, phosphate buffer is used as a blank control, and the final concentration of the sample is 10 mug/mL, 50 mug/mL and 100 mug/mL respectively. After adding the sample, the mixture is placed in 5% CO at 37 DEG C₂After culturing in an incubator for different times, adding 20 mu L of 3- (4, 5-dimethylthiazole-2) -2, 5-diphenyl tetrazolium bromide (5 mg/mL) into each hole, continuing culturing for 4 h, centrifuging, removing supernatant, adding 200 mu L of dimethyl sulfoxide, shaking at low speed for 10 min, and detecting the light absorption value at 570 nm.

The invention has the beneficial effects that: the invention aims at overcoming the defects of toxic and side effects, high cost and the like of the existing immunoregulation medicaments, aims at searching a natural immunoregulator, takes the ginseng as a starting point, focuses on the process control of the two-step enzymolysis of pepsin and trypsin, and prepares active polypeptide with specific peptide chain length, so that the immunocompetence is realized efficiently. The enzymolysis technology adopted by the invention is simple and efficient, the activity of the enzymolysis product can be tracked so as to achieve directional enzyme digestion, the cost waste is avoided, the obtained polypeptide has immunological activity, and a theoretical basis is provided for the application of the polypeptide in food and health care product industries.

Drawings

FIG. 1 shows the elution pattern (A) of G25 of the protein zymolyte of radix Pseudostellariae and the immunological activity (B) of each component.

FIG. 2 shows the elution profile of RP-HPLC (A) and the immunoreactivity of each fraction (B).

Fig. 3 is a F18 total ion flow diagram.

FIG. 4 is a peptide fingerprint of an immunomodulatory peptide.

FIG. 5 is a graph showing the proliferative activity of immunomodulatory peptides.

Detailed Description

Example 1

The amino acid sequence of the immunoregulation peptide is Arg-Gly-Pro-Pro-Pro.

The preparation method comprises the following steps:

the first step is as follows: pulverizing radix Pseudostellariae into powder with a traditional Chinese medicine pulverizer, and sieving with a 60-mesh sieve; weighing 5.0 g of radix pseudostellariae powder, adding 105 mL of 0.27 mol/L sodium hydroxide solution, leaching for 1 h at 52.1 ℃, centrifuging at 10,000 rpm for 20 min, taking supernatant, adjusting pH to 3.0 by using 1 mol/L hydrochloric acid, standing for 1 h, centrifuging at 5,000 rpm for 20 min, taking precipitate, and freeze-drying to obtain the radix pseudostellariae protein.

The second step is that: weighing 10.0 g of radix pseudostellariae protein, adding 100 mL of deionized water, adjusting the pH value to 2.0, adding 0.8 g of pepsin, placing in a boiling water bath for boiling for 10 min to terminate the reaction after carrying out enzymolysis for 5.0 h at 37 ℃, adjusting the pH value to 7.0, adding 0.8 g of trypsin, placing in a boiling water bath for enzymolysis for 3.0 h, centrifuging for 20 min at 10,000 rpm, taking the supernatant, and freeze-drying to obtain the radix pseudostellariae protein hydrolysate.

The third step: weighing 100 mg of radix pseudostellariae protein zymolyte, adding 5mL of deionized water, stirring until the radix pseudostellariae protein zymolyte is completely dissolved, centrifuging at 8,000 rpm for 20 min, taking supernatant, filtering through a 0.22 mu m filter membrane, and separating and purifying by utilizing sephadex G25: using deionized water as eluent, flow rate of 0.3 mL/min, detection wavelength of 214 nm, measuring the immunocompetence of eluent corresponding to each absorption peak, and measuring the elution curve (FIG. 1A) and immunocompetence of each obtained peak (FIG. 1B).

The fourth step: collecting the fraction G3 with highest immunological activity for reversed phase high performance liquid chromatography separation: weighing G3200 mg, adding 5mL deionized water, dissolving completely, filtering with 0.22 μm filter membrane, and loading 100 μ L. In the separation of the reversed-phase high performance liquid chromatography, acetonitrile solution with a concentration gradient of 0-55 v/v% and containing trifluoroacetic acid with a volume fraction of 0.05% is used as eluent for linear elution, a used chromatographic column is Gemini 5 mu C18, the flow rate is 1 mL/min, the detection wavelength is 214 nm, the immunocompetence of the eluent corresponding to each absorption peak is measured, and the elution curve (figure 2A) and the immunocompetence (figure 2B) of each obtained peak are measured.

The fifth step: the fraction F18 with the highest immunocompetence was collected, and after freeze-drying, the amino acid sequences of the fractions were identified by Nano LC-MS/MS. The amino acid sequence of the component is identified by using Nano LC-MS/MS, the total ion flow diagram is shown in figure 3, and then the ion peak of 77.35 min is identified by using MS/MS, so that the amino acid complete sequence is obtained (shown in figure 4): Arg-Gly-Pro-Pro-Pro (molecular weight 522 Da) is the immunoregulation peptide.

And a sixth step: the immunological activity was evaluated as the activity of promoting the proliferation of splenic lymphocytes in mice in vitro. The mouse spleen lymphocyte suspension is added into a 96-well plate, phosphate buffer is used as a blank control, and the final concentration of the sample is 10 mug/mL, 50 mug/mL and 100 mug/mL respectively. After adding the sample, the mixture is placed in 5% CO at 37 DEG C₂After culturing in an incubator for different times, adding 20 mu L of 3- (4, 5-dimethylthiazole-2) -2, 5-diphenyl tetrazolium bromide (5 mg/mL) into each hole, continuing culturing for 4 h, centrifuging, removing supernatant, adding 200 mu L of dimethyl sulfoxide, shaking at low speed for 10 min, and detecting the light absorption value at 570 nm. The immunomodulatory peptides of the invention reached a maximum spleen cell stimulation index of 1.25 at a stimulation time of 48h at a concentration of 100. mu.g/mL (FIG. 5).

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

SEQUENCE LISTING

<110> Fuzhou university

<120> preparation and method of immunoregulatory peptide

<130> 1

<160> 1

<170> PatentIn version 3.3

<210> 1

<211> 5

<212> PRT

<213> Artificial sequence

<400> 1

Arg Gly Pro Pro Pro

1 5

Claims

1. An immunomodulatory peptide, comprising: the amino acid sequence of the immunity polypeptide is Arg-Gly-Pro-Pro-Pro.