羊红细胞超氧化物歧化酶的研究

自羊红细胞分离得到一种高等电点的铜.锌-超氧化物歧化酶(Cu.ZnSOD)。其沉降系数(S)为3.23,亚基分子量为16600,等电点为8.50,紫外最大吸收峰位于259nm,酶分子中含有铜和锌,氨基酸组成特点与其它动物来源的Cu.Zn-SOD相同。该酶的比活性为5500U/mg(黄嘌吟氧化酶—细胞色素还原法);对KCN的抑制作用敏感,最适pH值为6。

Studies on the Superoxide Dismutase From Sheep Erythrocyte

A Cu.Zn-SOD with high isoelectric point (pI) was isolated from sheep erythrocytes according to McCord and Fridovich's method with a little modification. The purified enzyme was a highly homogeneous protein. Its pI is 8.50. The characteristic of amino acid composition is similiar to those of the Cu.Zn-SOD from other animals, but the contents of arginine and lysine are higher and exhibits absorption maximum at 259 nm. Its specific activity is 5 500 U/mg determined by the xanthine oxidase-cytochrome C reduction method. It's sensitive to KCN. Its specific activity could be reduced to less than 50% by KCN at 5 mmol/L and increased to 128% by 5 mmol/L NaN3, while 5 mmol/L or 15 mmol/L NaF and 0.01% As2O3 caused only a trivial effect.