Preparation And Isolation Of Three Kinds Of Aquatic Bioactive Peptides And Study On Their Immunogenic Activities

China's vast waters and diverse climates make China's aquatic living resources very rich,and the use of these resources and the development of deep processing technology for aquatic resources are beneficial to the development of the national economy and ecological protection.At the same time,aquatic organisms contain many nutrients and bioactive substances that can be developed into health foods or medicines with broad market prospects.In this paper,tilapia fish scales,sea cucumber viscera and carp fish bones were prepared from food processing,and tilapia peptide,sea cucumber peptide and carp peptide were prepared and studied.Three bioactive peptides were studied on mouse macropHage RAW264.7 immunomodulatory activity,and its mechanism of action.The results of this paper are as follows:(1)The preparation process of tilapia peptide is improved,the steps of acid-base water washing are optimized,the conditions of enzymatic hydrolysis are changed,the lamination filtration and the precision filtration step are added,and the preparation cost of tilapia peptide is lowered,and the yield and quality are improved.To study the immunological activity of tilapia peptide,it was found that tilapia peptide can induce the production of nitric oxide in RAW264.7 cells in a dose-dependent manner and induce the expression of nitric oxide synthase without cytotoxicity.Fish peptides have good immunopotentiating activity.(2)Preparation of sea cucumber peptide by enzymatic hydrolysis of sea cucumber viscera,and determination of its molecular weight distribution,amino acid composition,N-terminal structure,toxicity and purity.Studies on the immunological activity of sea cucumber peptides revealed that sea cucumber peptide can increase the immune activity of RAW264.7 cells and has no cytotoxic effect.Further studies have found that sea cucumber peptide promotes the secretion of TNF-? and IL-6 by activating NF-?B signaling pathway and MAPK signaling pathway,thereby promoting immune activity.(3)The squid peptide was prepared by enzymatic hydrolysis of carp fish bone,and it was found that squid peptide induced NO production in RAW264.7 cells,activated NF-?B signaling pathway and MAPK signaling pathway,promoted the secretion of TNF-? and IL-6,and promoted immune activity.Further separated by ion exchange chromatograpHy and gel filtration chromatograpHy to obtain the most pro-immunologically active salmon peptide Fr-1-1 group.