牦牛血抗氧化低聚肽肽段的鉴定及抗氧化活性研究

Identification of Antioxidant Oligopeptides from Yak Blood and Its Antioxidant Activity Study

采用LC-MS/MS法检测分子量<5 kDa的牦牛血抗氧化低聚肽的肽段组成及其序列,根据其氨基酸组成、肽段序列、活性位点以及分子量筛选出可能具有较好抗氧化活性的肽段7条,采用6种不同的体外抗氧化活性测定方法评价其抗氧化活性。结果表明,RRHPYFYAPELL、TLPDTEKQIKKQ、VLKDLKELVFYYLIMAKGGIVRS、EKKFWGKYLYEIARRHPYFYAPE、GPTQEFKKR、KFWGKYLYEIAR RHPYFYAPE、VSRSLGKVGTR这7条肽段均具有较好的体外抗氧化活性;其中,RRHPYFYAPELL在·OH清除力、ABTS+·清除力、DPPH·清除力、总抗氧化力、脂质过氧化抑制能力上均表现最好,GPTQEFKKR在还原力上表现最好。这与不同体外抗氧化活性检测方法中Leu、His、Tyr、Phe、Lys、Gln和Pro残基对抗氧化活性的影响不同有关。此外,与本研究前期试验制备的分子量<1 kDa的牦牛血抗氧化低聚肽比较,GPTQEFKKR、RRHPYFYAPELL在6个抗氧化指标上均无显著差异,表现出良好的体外抗氧化活性。

LC-MS/MS method was used to detect the peptide composition and sequence of yak blood antioxidant oligopeptides with a molecular weight lower than 5 kDa.According to its amino acid composition,peptide sequence,active site and molecular weight,seven peptides with better antioxidant activity were screened,and the antioxidant activity were evaluated by six different methods in vitro.The results showed that all seven peptides including RRHPYFYAPELL,TLPDTEKQIKKQ,VLKDLKELVFYYLIMAKGGIVRS,EKKFWGKYLYEIARRHPY FYAPE,GPTQEFKKR,KFWGKYLYEIARRHPYFYAPE,VSRSLGKVGTR had good antioxidant activity in vitro;among them,RRHPYFYAPELL showed the best capacity in·OH clearance,ABTS+·clearance,DPPH·clearance,total antioxidation and lipid peroxidation inhibition,GPTQEFKKR performed best in reducing capacity,which was related to the different effects of Leu,His,Tyr,Phe,Lys,Gln and Pro residues on antioxidant activities in vitro.Besides,compared with the yak blood antioxidant oligopeptide with molecular weight lower than 1 kDa prepared previously,GPTQEFKKR and RRHPYFYAPELL had no significant difference in 6 antioxidant indexes,showed good antioxidant activity in vitro.