【摘要】 以青蛤内脏为原料,应用碱性蛋白酶对其进行酶解,以DPPH清除率为指标,采用正交实验确定碱性蛋白酶酶解的最佳条件,测定酶解多肽对DPPH清除率、超氧自由基清除率、螯合力和还原铁的能力;使用琼脂糖凝胶电泳检测多肽对羟自由基诱导损伤的pBR322 DNA的保护作用,使用SDS-PAGE电泳测定青蛤多肽的分子量。结果表明青蛤内脏碱性蛋白酶酶解的最佳条件为温度50℃、时间4 h、酶添加量2 000μ/g、pH 9。得到的青蛤多肽在浓度为5 mg/mL时,DPPH的清除率为91.24%,羟自由基的清除率为62.83%,Fe²⁺的螯合力为61.13%,还原力为0.331。青蛤多肽对羟自由基诱导损伤的pBR322 DNA有一定的保护作用;该多肽的分子量范围为15²5 kDa。因此青蛤内脏经碱性蛋白酶酶解得到的多肽具有较好的抗氧化活性。更多还原

【Abstract】 In this study,Cyclina sinensis viscera were used to study its antioxidant activity and characteristic.The orthogonal experiment was adopted to determine the optimal hydrolysis conditions of C.sinensis polypeptide which effected by alkaline protease,and the ability of hydrolysates on DPPH free radical scavenging was determined,as well as the ability of scavenging superoxide free radical,chelating ability and the ability of reducing iron.The protective effect of the peptides against hydroxyl-radical-induced DNA damage was measured by DNA agarose electrophoresis and the molecular weight was detected by SDS-PAGE.The results showed that the optimum conditions of alkaline protease for hydrolysis were as follows:temperature 50 oC,hydrolysis time 4 h,E/S2000 U/g protein and Ph 9.0.As the C.sinensis polypeptide was 5 mg/mL,the rate of DPPH free radical scavenging was 91.24%,and that of the scavenging superoxide free radical,the ability of reduced iron were 62.83%and 61.13%,and the reducing power was 0.331.So,the polypeptide had a protective effect against DNA damage induced by hydroxyl radical.And,it’ s molecular weight was 15-25 kDa.The polypeptide isolated from C.sinensis exhibited an obvious capability of anti oxidation.更多还原