何首乌(Polygonum multif lorum Thunb.)叶 Cu·Zn-SOD 经硫酸铵盐析、离子交换柱层析及葡聚糖凝胶过滤等步骤, 被分离成两组 SOD 同工酶(SOD1 , SOD2), 它们被纯化到均一程度。SOD1 分子量为 32.4 kD, 亚基分子量为 16 .2 kD, 最适 pH 值为 5.0 , 在 60 ℃和 65℃时的半衰期分别为 14 min 和 8 min;SOD2 分子量为 30.5 kD, 亚基分子量为 15.9 kD, 最适 pH 值为 6.0 , 在 60 ℃和 65 ℃时半衰期分别为 32 min 和 16 min , 它由 274 个氨基酸残基组成, 不含 Cy s、T y r 和 T ry。SOD1 和 SOD2 每 mol 酶都含有 2mol Cu 和 2 mol Zn , 它们在紫外区最大吸收波长均为 275 nm 。
 

Two isoenzymes (SOD1 and SOD2)of Cu·Zn-SOD from the leaves of Polygonum multiflorum Thunb. were isolated and purified to apparent homogeneity .The relative molecular masses are about 32 400 and 30 500 for SOD1 and SOD2 respectively .SOD1 and SOD2 exhibite an optimum at pH about 5 .0 and 6 .0 respectively .The half-life values at 60 ℃and 65 ℃are respectively , 14 and 8 min for SOD1 and 32 and 16 min for SOD2 .SOD2 consistes of about 274 amino acid residues , from which Cys , Ty r and Try are absent .SOD1 and SOD2 contain 2 atoms of Cu and Zn per molecule of enzyme, and spectrum of the enzymes in the ultraviolet reg ion show s the same a peak at 275 nm .