99 results about "Invertase" patented technology

The invention relates to the technical field of biological catalysis, and discloses an L379A mutant enzyme for preparing rebaudioside I. The enzyme is obtained by the following mutations generated by UGT76G1: leucine of the 379th amino acid sequence is mutated into alanine; the enzyme can be applied to RA in-vitro conversion preparation of RI with higher utilization value, the conversion rate is higher than 50%, and the enzyme activity is remarkably improved by 7 times compared with the original enzyme catalytic conversion enzyme activity. The UGT76G1 mutant disclosed by the invention has the advantages that (1) the blank is filled, and a special enzyme catalyst capable of realizing efficient in-vitro synthesis of rebaudioside I (RI) is provided for the first time; 2) efficiency jump: the catalytic conversion rate is greatly increased from original about 7% to more than 50% (increase gt; and 3) stability and reliability: in the cross-scale reaction of 10mL to 5L, the catalyst has stable catalytic performance, shows excellent industrial application potential, and is suitable for popularization and application.

The invention provides a preparation method and application of a bacterium-enzyme-magnetic nano-cluster composite detoxicating agent, the detoxicating agent takes a Fe3O4-HAP nano-cluster as a magnetic core, the surface of the detoxicating agent is subjected to functional modification, a composite flora composed of bacillus amyloliquefaciens, lactobacillus plantarum and saccharomyces cerevisiae is loaded to form sclerotia, a chitosan shell layer is constructed on the outermost layer, and the bacterium-enzyme-magnetic nano-cluster composite detoxicating agent is prepared. And a compound enzyme consisting of aflatoxin Bdegrading enzyme, zearalenone hydrolase and deoxynivalenol invertase is immobilized. The carrier can efficiently and synchronously degrade aflatoxin, vomitoxin and zearalenone, and can realize rapid separation and recovery through an external magnetic field.

The invention provides an application of an OsINV2 gene in regulation and control of rice cold stress resistance. A nucleotide sequence of the OsINV2 is shown as SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3 or SEQ ID NO: 4. By revealing the key regulation and control effect of the vacuole sucrose invertase gene OsINV2 in rice low-temperature stress response, the molecular mechanism that the gene affects the cold resistance of plants by regulating the sugar metabolism balance in vacuoles is illustrated for the first time. The expression of the OsINV2 is regulated in a targeted manner through molecular marker-assisted breeding or a gene editing technology, so that the low-temperature survival rate in the seedling stage and the cold resistance in the booting stage of the rice can be remarkably improved, glumous flower degeneration and pollen abortion caused by low temperature are reduced, and meanwhile, the limitation of the cold resistance of varieties on geographical distribution is broken through; a theoretical support and a technical path are provided for breeding and adaptive popularization of cold-resistant rice varieties.

The invention relates to a multi-component ginseng extract containing ginseng polypeptide and a preparation method of the multi-component ginseng extract. The preparation method comprises the following steps: S1, preparing ginseng powder from a ginseng raw material; mixing the ginseng powder with an acidic buffer solution, and carrying out presoaking treatment and homogenate dissolution promoting treatment to obtain ginseng primary pulp; s2, mixing the wall-breaking enzyme system with the ginseng primary pulp, and performing acid wall-breaking treatment to obtain wall-broken primary pulp; mixing an invertase system with the wall-broken primary pulp, and carrying out enzymolysis synchronous glucoside conversion treatment to obtain a crude extract; s3, filtering and separating the crude extracting solution to obtain an extract containing the ginseng polypeptide; the pH values of the ginseng primary pulp, the wall-broken primary pulp and the crude extract are in a range of 4.0-6.0; the wall breaking enzyme system comprises pectinase and cellulase; the invertase system comprises beta-glucosidase and acid protease. The technical problems that in the prior art, a ginseng extract is complex in extraction process, multiple active ingredients are difficult to efficiently extract at the same time, the product quality is low, and the biological activity is poor are solved.

The invention provides earthworm protein peptide as well as a preparation method and application thereof, and belongs to the technical field of medicines. The preparation method comprises the following steps: drying and crushing earthworms to obtain earthworm powder, adding the earthworm powder into water, adding immobilized compound enzyme for enzymolysis, carrying out magnet separation, adjusting the pH value of enzymatic hydrolysate for precipitation, collecting solids, adding the solids into water, adding a purifying agent for adsorption separation, adding the solids into a deep eutectic solvent, heating for desorption, carrying out magnet separation, carrying out ultrafiltration on residual liquid, and collecting protein peptide to obtain the earthworm protein peptide. The immobilized compound enzyme is prepared by immobilizing modified snail protease and alkaline protease on chitosan modified MOF / magnetic microspheres; the purifying agent is a passivated angiotensin converting enzyme immobilized magnetic agar ball. The high-activity earthworm protein peptide has the advantages of simple preparation method, high purity, good inhibition effect on angiotensin converting enzyme, safety, high efficiency, no side effect, good antihypertensive effect on hypertensive patients, good patient compliance, and wide application prospect.

The invention relates to the field of synthetic biology, metabolic engineering and fermentation engineering, and discloses a genetically engineered bacterium and application thereof in production of alpha-ketoglutaric acid.The genetically engineered bacterium comprises the steps that the genetically engineered strain with escherichia coli BW25113 or corynebacterium glutamicum ATCC13032 as a host is constructed; overexpression type isocitrate dehydrogenase genes are integrated through chromosomes, alpha-ketoglutarate dehydrogenase complex genes are knocked out, NADPH invertase is overexpressed through plasmids, and exogenous AKG transporter protein is introduced, so that metabolic flux directional regulation and control and product efflux enhancement are realized; meanwhile, a staged fermentation process is adopted and comprises dynamic gradient adjustment of inorganic phosphorus concentration and two-stage pH control. According to the method, the AKG yield of 78.2 g / L can be obtained under the 5L tank scale, the sugar acid conversion rate reaches 0.68, and the method has the advantages of being high in yield, low in byproduct and controllable in cost. The obtained AKG is suitable for a plurality of fields such as medical intermediates, functional foods and cell culture additives, and has wide industrial application prospects.

The utility model relates to the technical field of fermentation tank cooling, in particular to a cooling circulation system of a biological fermentation tank for bose invertase, which comprises a heat exchange cylinder with an upward opening, the fermentation tank is fixedly arranged in a fermentation barrel, a heat exchange cavity is arranged between the fermentation tank and the inner wall of the fermentation barrel, and two sides of the heat exchange cavity are respectively communicated with a water inlet pipe and a water outlet pipe. The water inlet pipe is respectively communicated with a hot water inlet pipe and a cold water inlet pipe through a three-way pipe, the hot water inlet pipe is communicated with a warm air inlet pipe, the cold water inlet pipe is communicated with a first water pump in the reservoir, the water outlet pipe is controlled by a first valve, and the hot water inlet pipe and the cold water inlet pipe are respectively controlled by a second valve and a third valve; a discharge port of the fermentation tank is communicated with a discharge pipe, the discharge pipe penetrates through the heat exchange cylinder and is provided with a discharge valve, and the reservoir is communicated with a cold water pipe. By using the fermentation tank, it can be guaranteed that the fermentation tank is heated in winter and cooled in summer, so that the temperature in the fermentation tank can be maintained between 18 DEG C and 25 DEG C, and better fermentation of the fermentation tank is guaranteed.

The invention discloses a method for synthesizing D-psicose by multi-enzyme immobilized cascade catalysis of sucrose, and belongs to the technical field of food production. The method provided by the invention comprises the following steps: respectively immobilizing sucrose invertase, glucose isomerase and epimerase by utilizing protein affinity immobilization purification magnetic beads to prepare immobilized enzyme, carrying out enzymatic reaction by taking sucrose as a substrate, and converting the sucrose into D-psicose step by step. Experimental results show that the method provided by the invention can effectively convert cane sugar, glucose and fructose which are easy to absorb into D-psicose which is difficult to absorb; after the enzymatic reaction, the immobilized enzyme can be effectively recovered through rapid separation and can be reused, so that the production cost is saved. The invention provides a low-cost and high-efficiency production method for the production of D-psicose, and the method has a wide application prospect.

The application discloses a polypeptide-based anti-fouling electrochemical sensor and a construction method and application thereof. In the application, cysteine is used as an anchoring end, an alpha-helix structure is formed by inserting polyproline to give a supporting effect to the whole peptide, then angiotensin converting enzyme inhibitory peptide (KSRE) and alpha-glucosidase inhibitory peptide (EKDER) are used as branches to prepare the anti-fouling polypeptide. The anti-fouling polypeptide has a better anti-fouling effect than other anti-fouling polypeptides, and the working electrode is modified by the anti-fouling polypeptide to prepare an anti-fouling electrochemical aptamer sensor for detecting AFB1, so that the anti-pollutant interference effect of the sensor can be greatly improved, the accuracy and sensitivity of AFB1 detection can be improved, and the anti-fouling electrochemical aptamer sensor has a wide application prospect.

This invention relates to a process for the production and purification of fructooligosaccharides (FOS) and the product obtained by such process having low or no residue of glucose, or fructose, or sucrose, with the FOS having a different ratio of oligomers (GF2, GF3, GF4, GF5 and GF6) and their isomers, to be used in animal and human nutrition due to their superior properties of modulating the intestinal microbiota and direct and indirect immunomodulation. The process for producing and purifying fructooligosaccharides according to the invention employs at least two microbes or yeasts, simultaneously or separately, with one of the microbes or yeasts being unable to produce extracellular invertase in a medium containing sucrose, in order to convert sucrose into fructooligosaccharides (FOS), with total consumption of glucose from the medium and evaporation of alcohol or ethanol during drying of the final product.

The present invention discloses a method for preparing milk-derived angiotensin-converting enzyme inhibitory peptides by fermentation with composite strains, which belongs to the fields of microbial technology and fermentation. The ratio of whey protein hydrolysate with a molecular weight below 1000 Da and the angiotensin-converting enzyme inhibition rate in the milk-based fermentation broth are used as evaluation indicators. The composite strain Lactobacillus helveticus ( Lactobacillus helveticus , CICC: 20289), composite strain Pediococcus dilactici ( Pediococcus acidilactici , CICC:20719) were rescreened to obtain strains with excellent whey protein hydrolysis performance and high angiotensin-converting enzyme inhibitory peptide production capacity. The two composite strains obtained from the rescreening were enriched and cultured separately, and then inoculated into skim milk powder culture medium at a specific compound ratio. Through composite fermentation, the angiotensin-converting enzyme inhibitory peptide content in the milk-based fermentation product was increased. The process of this invention is rationally designed and highly operable. It provides a reference for further increasing the content of small molecule functional peptides in fermented dairy products, efficiently preparing milk-derived angiotensin-converting enzyme inhibitory peptides, and improving the nutritional value of dairy products, and has great application prospects.

The present application relates to the field of agricultural biotechnology, and particularly relates to a molecular marker capable of identifying allelic variations of a soluble acid invertase gene AcoInv-1 in pineapple fruits and application thereof. The molecular marker is amplified by using the following primers: forward primer 5-CTGCGAAATGAACTAGTCAACTC-3 and reverse primer 5-TAGAGAACCGTTCTTGG AATGG-3. The primers can identify allelic variations of the soluble acid invertase gene AcoInv-1 in pineapple fruits, i.e. AcoInv-1a and AcoInv-1b. It is found through research that the two allelic variations are extremely significantly related to the total sugar content of the pineapple fruits. It is proved through verification that the pineapple material of the AcoInv-1a type is related to high sugar content, and the pineapple material of the AcoInv-1a and AcoInv-1b types is related to low sugar content. The application of the molecular marker obtained by the present application in selecting pineapple varieties with high sugar content potential will help to accelerate the breeding selection cycle.

The present application relates to the field of plant genetic breeding, and particularly relates to a kind of evaluation method of asparagus yield. Including the following steps: S1, obtaining young plant period asparagus;S2, measures i variety of young plant period asparagus following parameters: photosynthetic rate A, ribulose-1,5-bisphosphate carboxylase / oxygenase activity B, leaf dry weight per unit area C, acid invertase activity D and root crown ratio E;The measurement sample of the acid invertase activity D is the tender stem of young plant period asparagus at 10-30cm from top;S3, according to the formula, the evaluation value is calculated, and the evaluation value is used to evaluate the yield of asparagus. The evaluation value obtained by using the above measurement index and calculation formula, and the significance level obtained by SPSS software is used to evaluate the yield of asparagus. The yield potential of asparagus can be comprehensively evaluated from the genetic point of view in a short time. Using the evaluation method of the present application, high-yield asparagus varieties can be selected in a short time without tracking for many years.

The invention discloses a micropterus salmoides gene modification method which comprises the following steps: step 1, encoding a precursor gene of micropterus salmoides GLP according to a published micropterus salmoides genome database; 2, obtaining a translated micropterus salmoides GLP precursor protein sequence according to the precursor gene for coding the micropterus salmoides GLP; step 3, successfully predicting a mature protein sequence of the micropterus salmoides GLP according to a comparison result of the cloned sequence for coding the micropterus salmoides GLP precursor gene, a translated protein sequence, a recognition site of 1 / 3 of a prohormone converting enzyme and sequences of different fish GLPs; and 4, transforming the mature protein sequence of the GLP of the micropterus salmoides according to the mature protein sequence of the GLP of the micropterus salmoides and the recognition site of the DPPIV enzyme. The GLP is modified according to a mature protein sequence of the GLP, and the modified protein can realize a regulation effect on fish glycolipid metabolism and is expected to be developed into a feed additive for promoting glycolipid utilization.

The present invention discloses a highly active ginseng fermented product and its application. Ginseng is fermented using a composite strain composed of independently screened plant lactobacillus Byf‑r‑01 and grape juice spore Hansen yeast Byf‑j‑01. The composite strain metabolic enzyme system is highly complementary, and the prototype ginsenosides are efficiently converted into rare ginsenosides in a collaborative manner, while simultaneously improving the content of polyphenols, flavonoids, alkaloids and volatile oils. The present invention adds chitosan-polyaspartic acid complex to neutralize lactic acid and maintain pH stability. At the same time, it promotes the proliferation of composite strains as a nitrogen source, significantly improves strain biomass and the activity of saponin-related converting enzymes, and promotes the conversion of ginsenosides. The highly active ginseng fermented product prepared by the present invention has both strong antioxidant and anti-fatigue functions. It has been confirmed by animal experiments that it can prolong the exhaustive swimming time of mice, reduce blood urea nitrogen levels, increase liver / muscle glycogen reserves, and significantly alleviate lactic acid accumulation after exercise, providing a new path for the development of high value-added functional products for ginseng.

The invention discloses a Thomasclavia ramosa CMLF06 strain, saponin converting enzyme and application of the Thomasclavia ramosa CMLF06 strain and the saponin converting enzyme, the Thomasclavia ramosa CMLF06 strain is preserved in China General Microbiological Culture Collection Center, the preservation address is No.3, No.1 yard, Beichen West Road, Chaoyang District, Beijing, the preservation date is January 25, 2024, and the preservation number is CGMCC NO. 41093. The invention further discloses a method for preparing the saponin converting enzyme. The Thhomasclavia ramosa CMLF06 strain can convert ginsenoside to generate rare ginsenoside and sapogenin, the saponin converting enzyme GE001065 can convert ginsenoside and notoginsenoside to generate various rare ginsenoside in the presence of ethanol, the activity and stability of the enzyme GE001065 in an ethanol solution and a methanol solution are remarkably improved, the enzyme GE001065 shows an activation effect in various alcohols, and the enzyme GE001065 can be used for preparing the rare ginsenoside. The method can be used in the fields of medicine and functional food.

The invention relates to the field of protein, in particular to a milk-derived peptide APPSPIGVF with antihypertensive activity as well as a preparation method and application of the milk-derived peptide APPSPIGVF, and the amino acid sequence of the milk-derived peptide APPSPIGVF is Ala-Pro-Pro-Ser-Pro-Ile-Gly-Val-Phe. An angiotensin converting enzyme activity inhibition experiment, an alpha-amylase activity inhibition experiment and a dipeptidyl peptidase-4 activity inhibition experiment prove that the milk-derived peptide APPSPIGVF has very good functions of resisting hypertension and reducing blood sugar. The milk-derived peptide APPSPIGVF disclosed by the invention has an anti-hypertension capability, and can be used for remarkably inhibiting the activity of alpha-amylase and dipeptidyl peptidase-4, improving the capability of resisting chronic diseases such as hypertension and hyperglycemia of an organism, reducing the morbidity of the organism and improving the quality of life; the method has very important significance for developing food, health care products and medicines with the functions of resisting hypertension and reducing blood sugar.

The invention discloses a biosynthesis process of creatine monohydrate, and belongs to the technical field of bioengineering. The invention discloses a creatine monohydrate biosynthesis method, which is characterized in that sarcosine invertase is utilized to catalyze chloroacetic acid and monomethylamine to generate N-alkylation reaction so as to prepare sarcosine, and then creatine monohydrate is generated under the catalysis of the creatine invertase, the process is mild in reaction condition, the temperature is 25-37 DEG C, the pH is 6.0-8.0, the energy consumption is lower, the conversion efficiency is high, the environment is protected, and the economical efficiency is high. The invention provides a new synthesis method for sustainable synthesis of creatine monohydrate, and provides a new idea for industrial production of creatine monohydrate.

Disclosed are recombinant mutant invertase enzymes. Also disclosed are pharmaceutical compositions comprising an invertase enzyme, e.g., a recombinant mutant invertase enzyme and an optional isomaltase enzyme. The enzymes and compositions can be used, among other things, to treat sucrase-isomaltase deficiency (e.g., congenital sucrase-isomaltase deficiency or acquired sucrase-isomaltase deficiency).

The invention discloses a preparation method and application of an edible grass leaf source active peptide with ACE (angiotensin converting enzyme) inhibitory activity, and belongs to the technical field of biological active peptides. The preparation method comprises the following steps: firstly, extracting azolla filliculoidas protein from azolla filliculoidas powder by adopting an ultrasonic-assisted alkali-solution and acid-isolation method; dissolving a certain amount of rumex hanus powder in distilled water, adjusting the pH value of the solution, carrying out water bath preheating, and adding neutral protease for enzymolysis; and carrying out ultrafiltration and DEAE Sepharose FF anion gel column separation on the obtained enzymolysis product to obtain the azolla filliculoidas source active peptide with efficient angiotensin converting enzyme inhibitory activity. The preparation method is simple in process, mild in condition and easy to popularize, the obtained active peptide has wide application prospects in development of functional food, health care products and antihypertensive drugs, and effective utilization and value improvement of azolla filliculoidas protein resources are facilitated.

The present disclosure provides pharmaceutical compositions comprising fibronectin based scaffold domain proteins that bind, for example, proprotein convertase subtilisin kexin-9 (PCSK9).

This invention discloses a strain of *Lactobacillus casei* that produces thermostable invertase and its applications. This strain was deposited on August 14, 2023, at the China Center for Type Culture Collection (CCTCC), Wuhan, Hubei Province, China, with accession number CCTCCNO: M20231470. The *Lactobacillus casei* provided by this invention is easy to culture and can produce high levels of thermostable invertase. Its probiotic powder can rapidly degrade sucrose and prevent sucrose intolerance. The metabiotic prepared from this strain can also effectively degrade sucrose and prevent sucrose intolerance.

The present invention discloses a betaine composition having a blood pressure lowering effect and a preparation method thereof, belonging to the technical field of pharmaceutical compositions. The preparation method includes: preparing a tablet core, preparing a primary coating solution, preparing a secondary coating solution, primary coating, and secondary coating; the preparation of the primary coating solution includes: preparing a filler and primary mixing; the preparation of the secondary coating solution includes: preparing a supramolecular composition and secondary mixing; the betaine composition prepared by the present invention can avoid the problem of too low blood pressure after the use of the prepared betaine composition by controlling the release rate of the angiotensin converting enzyme inhibitor. The prepared betaine mixture has good storage stability, high qualified rate, and small difference in the content of the angiotensin converting enzyme inhibitor among the prepared betaine mixtures.

This invention belongs to the field of biotechnology, specifically relating to a multifunctional bioactive peptide based on millet protein and its preparation method. The amino acid sequence of the bioactive peptide is shown in SEQ ID NO: 1. The bioactive peptide of this invention can activate alcohol dehydrogenase activity and inhibit xanthine oxidase and angiotensin-converting enzyme activity. It has the characteristics of small molecular weight and easy absorption. Furthermore, bioinformatics analysis predicts that it has advantages such as non-toxicity, non-carcinogenicity, high hydrophilicity, and long half-life. It can be used to develop drugs with therapeutic effects on diseases such as hangover relief, uric acid reduction, and blood pressure reduction, and has broad application prospects.

The invention discloses a multifunctional bioactive peptide from highland barley and application of the multifunctional bioactive peptide. The bioactive peptide has an amino acid sequence as shown in SEQ ID NO: 1. The multifunctional bioactive peptide disclosed by the invention has the activity of inhibiting angiotensin converting enzyme, the activity of inhibiting dipeptidyl peptidase-4, the antioxidant activity and the anti-inflammatory activity, can be used for developing polypeptide medicines or functional foods with a disease treatment effect, and has a good application prospect.

The invention provides an industrial hempseed meal fermentation product for reducing blood pressure as well as a preparation method and application thereof, and belongs to the technical field of deep processing of industrial hempseed meal. The method for preparing the industrial hempseed meal fermentation product for reducing blood pressure comprises the following steps: carrying out alkali dissolution and acid precipitation on industrial hempseed meal to obtain industrial hempseed protein, and mixing the industrial hempseed protein and water according to a solid-liquid ratio of 1g: (20-30) mL to obtain a fermentation culture medium; and inoculating a lactobacillus plantarum seed solution into the fermentation culture medium, fermenting at 35-40 DEG C for 65-72 hours to obtain a fermentation solution, centrifuging, and taking a supernatant to obtain the industrial hempseed meal fermentation product. The industrial hempseed meal leavening prepared by the method disclosed by the invention has an obvious function of inhibiting the activity of angiotensin converting enzyme in vitro, shows higher antihypertensive activity in a hypertensive animal in-vivo experiment, and can influence the concentration of a plurality of substances related to the antihypertensive activity.

The invention provides a reagent and a kit for detecting ADP (adenosine diphosphate), a detection method of ADP and application of the detection method, and belongs to the technical field of ADP detection. The reagent for detecting the ADP comprises ATP sulfating enzyme, pyrophosphatase, an enzyme inhibitor, invertase for catalyzing the ADP into ATP, a substrate of the invertase, bioluminescent enzyme and a substrate of the bioluminescent enzyme, wherein the enzyme inhibitor inhibits the activity of the ATP sulfating enzyme and the pyrophosphatase. According to the present invention, the ADP detection accuracy and the ADP detection sensitivity are high, the fluorescence signal is stable, and the reagent can be used for detecting the enzyme activity of phosphotransferase and / or ATP hydrolase.

Disclosed are, inter alia, combinations comprising a first antisense (e.g., first double stranded RNAi (dsRNAi)) agent for inhibiting expression of proprotein convertase subtilisin kexin 9 (PCSK9), for example, human PCSK9, and a second antisense agent (e.g., second dsRNAi agent) for inhibiting expression of lipoprotein (a) (Lp(a)); pharmaceutical compositions including the same, and methods of treatment using the same.

This invention provides a sea buckthorn seed protein peptide, its preparation method, and its application, relating to the field of plant protein peptide extraction technology. The preparation method includes: pulverizing defatted sea buckthorn seed residue, performing ultrasonic-assisted extraction, adjusting the pH value to precipitate, and centrifuging to obtain a protein extract; adding a complex protease composed of alkaline protease, flavor protease, and neutral protease in a specific enzyme activity ratio for targeted enzymatic hydrolysis; purifying the hydrolysate sequentially through a 3kDa ultrafiltration membrane and a 1kDa nanofiltration membrane, collecting the permeate; adding an encapsulating agent and spray drying to obtain the final product. The sea buckthorn seed protein peptide prepared by this method has a molecular weight of less than 3kDa (≥85%), a purity of ≥90%, and exhibits excellent DPPH free radical scavenging ability and angiotensin-converting enzyme inhibitory activity. This invention achieves efficient extraction of sea buckthorn seed protein and targeted enrichment of active peptides. The product can be used as a functional food, health product, or pharmaceutical raw material for antioxidation and blood pressure reduction.

The invention belongs to the technical field of development of plant-derived bioactive peptides, and discloses a preparation method and application of a moringa seed antihypertensive polypeptide. Moringa seed polypeptide with the activity of inhibiting angiotensin converting enzyme (ACE) is separated and purified from moringa seed crude protein, nine moringa seed ACE inhibitory peptides with brand-new sequences and the effect of reducing blood pressure are finally obtained through structural identification, activity screening and solid-phase synthesis, sequence modification is conducted on polypeptide PLVRRAIY with the highest activity, and the trypsin enzymolysis resistance of the polypeptide PLVRRAIY is improved. Molecular level and animal experiments show that both the original peptide PLVRRAIY and the modified peptide PPVQQAIY have significant ACE inhibitory activity and antihypertensive effect, the trypsin degradation resistance of the modified peptide in the gastrointestinal tract environment is enhanced, the stability is significantly improved, and a new resource is provided for development of natural antihypertensive polypeptide drugs.