Study On Modification And Bioactivity Of Andrias Davidianus Peptide

Andrias davidianus is rich in nutritional value,containing a variety of natural bioactive substances such as high-quality protein,abundant amino acids and trace elements.The Andrias davidianus peptide can improve physiological metabolism,promote protein synthesis,delay aging,improve the body’s immunity and hematopoietic function.It has positive effect on preventing pernicious anemia and cardiovascular and cerebrovascular diseases.Molecular modification of peptide can confer excellent water solubility,low antigenicity and function.Zinc plays an important role in improving immunity and repairing wounds.There is no report on the preparation and activity of Andrias davidianus peptide-zinc chelate.Therefore,we modified Andrias davidianus peptide with zinc and optimized its production process to prepare high chelating activity of Andrias davidianus peptide.By studying the structure and biological activity of Andrias davidianus peptide-zinc,it is beneficial to improve the application value of Andrias davidianus peptide in food and medicine fields.The main conclusions are as follows:（1）Determination of preparation technology of peptide-zinc chelate for Andrias davidianus.Peptide-zinc chelates were prepared by single factor and response surface method.The optimum preparation conditions were the mass ratio of peptide to zinc sulfate of 25:1,chelating p H of 5.18,alcohol precipitation ratio of 5,peptide concentration of 0.04 g/m L,chelating temperature of 60℃,chelating time of 60 min.The chelation rate and chelation yield of peptide-zinc chelate were 88.57%and 57.25%,respectively.Fourier infrared spectrum analysis showed that the peptide reacted with zinc ions to form a new compound different from the parent molecule.Amino,carboxyl and carbonyl groups on the peptide bond were involved in chelating reaction and combined with zinc ions to form new substances.Ultraviolet spectrum analysis showed that the characteristic peaks of peptide-zinc chelate compound were blue shifted and decreased,and the shift of absorption peak and the change of peak intensity indicated that the peptide-zinc chelate formed a new substance.Scanning electron microscope（SEM）analysis showed that Andrias davidianus peptide were smooth and regular spheroidal granules,and the Andrias davidianus peptide-zinc chelates were irregular and mostly polymerized.（2）ADP-Zn1 and ADP-Zn2 absorption peaks of peptide-zinc chelate were obtained by LH-20 chromatography.The coagulation activity and glucose inhibition of Andrias davidianus peptide-zinc chelate r were studied by multiple dilution method.The results showed that Andrias davidianus peptide-zinc chelate had agglutination effect on sheep blood cells with a titer of 2⁵.The agglutination titer of the absorption peak ADP-Zn1 was 2³,and that of ADP-Zn2 was 2².The results showed that the agglutination of peptide-zinc chelates could be inhibited by glucose,D-（+）-mannose,D-galactose,arabinose,rhamnose-l-sorbate,D-（+）-xylose and L-fucose,but not by glycoprotein.149 peptides were identified from ADP-Zn1 samples by LC-MS/MS,and 113kinds of peptide-zinc source proteins were matched,and 214 peptide matching proteins were identified by secondary mapping.A total of 105 peptides were identified in ADP-Zn2 samples,and 105 kinds of peptide-zinc source proteins were identified.（3）In vitro antioxidant assay showed that peptide and peptide-zinc chelate had concentration-dependent scavenging effects on DPPH·,ABTS⁺·,·OH and O₂^-·.The Andrias davidianus peptide-zinc chelates showed stronger ACE inhibitory activity than the Andrias davidianus peptide-zinc chelate.The effects of peptide-zinc chelate on B.subtilis,S.aureus,S.putrefaciens and E.aerogenes were significantly inhibited by filter paper and liquid culture.The results of respiratory inhibition showed that peptide-zinc chelates mainly inhibited the PPP pathway of E.aerogenes respiratory metabolism,and it mainly inhibits the EMP pathway in respiratory metabolism of B.subtilis,S.putrefaciens and S.aureus.Proliferation rate method showed that peptide-zinc chelate could promote proliferation of RAW246.7 macrophages.Ultraviolet spectrophotometry showed that peptide-zinc chelate inhibited the growth of saccharomyces cerevisiae cells.ADP-Zn1 inhibited the growth of saccharomyces cerevisiae cells,and ADP-Zn2 promoted the growth of saccharomyces cerevisiae cells.