Activity And Selection In Silico Of Antioxidant Peptides And ACE Inhibitory Peptides From Squid Tentacle

Squid is aquatic product with high content protein and low content fat.It is important to use squid to prepare bioactive peptides.In this paper,the Todarodes pacificus tentacle and Illex argentinus tentacle were selected as the research material.The antioxidant peptides and ACE inhibitory peptides were separation by enzymatic hydrolysis,ultrafiltration fractionation techniques,and gel chromatography column method,in order to explore the antioxidant activity and ACE inhibitory activity of the squid tentacle.Finally,exploring small molecular peptides with antioxidant activity and ACE inhibitory activity of peptides of Todarodes pacificus myosin in silico.The main research contents are as follows:(1)Study on the optimal enzymatic hydrolysis of squid tentacle peptides:Taking the DH as an indicator,papain is used as an enzyme for enzymatic hydrolysis.Through response surface analysis experiments,it was found that the amount of enzyme added,temperature and liquid-to-materials ratio have significant effects on the response values.The optimal enzymatic hydrolysis conditions for the Todarodes pacificus tentacle are 1.41%(w/w),temperature 51.08?,liquid-to-material ratio 2.26:1(v/v),time was 6 h,and the DH was 30.16±0.31%.The optimal parameters of Illex argentinus tentacle were 1.43%(w/w),temperature 50.86?,6 h enzymatic hydrolysis,liquid-to-material ratio 2.06:1(v/v),then,DH was 28.98 ± 0.31%.The higher DHbasci for subsequent experiments.(2)Separation and purification of squid tentacle peptides:Firstly,the DPPH scavenging rate(20.38±0.97%and 18.49±0.7%),hydroxyl radical scavenging rate(9.35± 0.57%and 7.75±0.36%),total antioxidant capacity(0.070±0.003 U/mL and 0.376±0.004 U/mL)and ACE inhibition(45.93±0.31%and 42.03±0.19%)of the enzymatic hydrolysate of the Todarodes pacificus tentacle and Illex argentinus tentacle were determined.The results showed that the antioxidant activity and ACE inhibitory activity of Todarodes pacificus tentacle were higher than those of the Todarodes pacificus tentacle.Then,using ultrafiltration fractionation and Sephadex G-10 gel column to obtain power DPPH free radical scavenging of SPH-?2(DPPH scavenging rate of 25.86 ± 0.59%and 25.95 ± 0.56%)and ACE inhibition(ACE inhibition rate of 75.78±0.63%and 75.08 ±0.71%).After UPLC measurement,the MW of Todarodes pacificus SPH-?2 and Illex argentinus SPH-?2 were determined to be 634.84 Da and 637.2 Da,respectively.(3)Explored the antioxidant peptides and ACEIP derived from Todarodes pacificus in silico.The plant proteases and POP were used for the hydrolysis of squid myosin heavy chain:A total of 13 antioxidant peptides and 126 ACEIP were predicted from myosin hydrolysates by the BIOPEP-UWM and ATHprn databases.Then,2 antioxidant peptides.30 active peptides,including 21 known peptides and 9 new peptides with ACE inhibitory,were screened by predicting toxicity,allergenicity,gastrointestinal stability,and intestinal epithelial permeability.Moreover,the interaction mechanisms of ACEIP with ACE were evaluated by molecular docking.The result indicated that QY and QM in the new peptides had the potential inhibitory effects on ACE.They could bind to Zn(?)by coordination and were deeply buried in the hydrophobic pockets Si,S2 and S1' of ACE by hydrogen bonding and hydrophobic interactions.This work demonstrated that Todarodes pacificus was a good source of antioxidant peptides and ACE inhibitory peptides and can also be used as a protocol for exploring food-derived antioxidant peptides and ACE inhibitory peptides in silico.