绿茶抗氧化肽的分离纯化与抗氧化活性研究

Study on the purification and antioxidant activity of the antioxidant peptide from green tea

通过饱和硫酸铵盐析的方法从干绿茶中提取得到绿茶粗蛋白，粗蛋白透析除盐后用葡聚糖凝胶SephadexG-75层析柱进行凝胶色谱法分离纯化，收集具有抗氧化活性的蛋白样品，并冷冻干燥，同时利用SDS—PAGE的方法对凝胶分离后收集的活性样品进行纯度的鉴定及相对分子质量的测定，并采用·OH清除法及O2-·清除法研究绿茶抗氧化多肽纯品的抗氧化活性。结果表明，绿茶抗氧化多肽经葡聚糖凝胶sephadexG-75层析柱后，得到很好的分离和纯化，在SDS—PAGE电泳图谱上只有1条条带，其相对分子质量为2—15ku；绿茶抗氧化多肽对·OH具有很强的清除作用，其半清除浓度（IC50）为0．069μg/mL；对O2-·也具有较强的清除作用，其半清除浓度（IC50）为18．462μg／mL，与V。的清除作用（IC50为11．186μg／mL）相当。

The crude proteins of green tea were extracted by saturated ammonium sulfate precipitation from dry green tea in this experiment,and the dialyzed crude proteins were purified further by dextran gel Sephadex G-75 column.The purity and relative molecular weight of the purified samples were determined by SDS- PAGE method.The scavenging capacity toOH and 02- free radical were also examined in order to investigate antioxidant activity of the antioxidant peptide.The results showed that the antioxidant peptide of green tea was purified completely by dextran gel Sephadex G-75 Column,only 1 band on SDS-PAGE,and its relative molecular weight was 2-15ku.The green-tea antioxidant peptide had strong scavenging ability to hydroxyl radical and its half scavenging concentration was 0.069μg/mL.And it also had strong scavenging ability to superoxide anion radical, and its half scavenging concentration was 18.4621μg/mL,which had little difference from Vc scavenging effect（IC50 11.1861μg/mL）.