Study On The Extraction And Bioactivity Of Peptides From Mustelus Griseus' Skin

Shark skin is rich in protein.In this study,we using modem enzymatic biology technology,using Mustelus griseus skin as raw material,papain as hydrolytic enzyme,antioxidant capacity as index,using gradient optimization method to conduct single factor experiment on the amount of enzyme,pH,temperature and time.On this basis,the center compound test was used to optimize the preparation of antioxidant mixed peptidess,and its physical and chemical properties and efficacy were investigated.Results are as follows,the amount of enzyme was 4%,pH 4.5,the temperature was 50.5?,and enzymatic hydrolysis time was 3 h.Under the condition the hydrolysate has strongest antioxidant capacity.The ultraviolet absorption peak of antioxidant peptides was 220 nm and 280 nm,and it has good moisture absorption and moisture retention,which were(44.6±0.3 5)%and(70.1±0.68)%,when there's 43%water in the air,The IC50 of DPPH radical and ABTS radical were 0.55 and 0.28 mg/ml.Moreover,the peptides can scavenge free radicals and protect DNA from oxidative damage,when the concentration is 10 mg/ml.The molecular weight of shark skin peptides was determined by MALDI-TOF-MS.The results showed that they were around 1500-1900 Da and were easily absorbed.Mushroom tyrosinase was used to explore the inhibition effect of peptides on melanin,the ICso of which was 0.4 mg/ml.Based on this,the effect of peptides on melanogenesis in B16F10 cells was studied.When the concentration of the peptides was 1280 ?g/ml,the proliferation of L02 and B16F10 cells was not significantly changed.It indicated that peptides had no cytotoxicity.When treated with peptides,the melanin content and tyrosinase activ:ity were decreased in B16F10 cells.Western blot and RT-qPCR were used to detect the transcription and translation of melanogenesis-related genes.The results showed that the peptides down-regulate the MTTF,TYR and TRP-1.And it inhibited the expression of melanogenesis-related proteins in a dose-dependent manner,including MCIR,a-MSH,MITF,TYR,TRP-1.The relationship between peptides and melanin inhibitory pathways was studied Both the intracellular cAMP content and the phosphorylation level of CREB showed a declining trend.It was speculated that the peptides may inhibit melanin synthesis through the cAMP-CREB pathways.Using zebrafish as a model,we found that 500 ?g/ml of peptides could inhibit the melanin in zebrafish,effectively.The ab ove results provide a theoretical basis for application of'shark skin peptides in cosmetics in the future.