甘蓝细胞溶质超氧化物歧化酶的纯化及性质研究

Studies on Purification and Properties of Superoxide Dismutase from Cabbage Plasma

通过对甘蓝细胞溶质SOD的纯化及性质研究 ,开拓制备SOD的廉价原料来源。经硫酸铵沉淀、SephadexG 10 0凝胶过滤和DEAE DE5 2层析 3个步骤 ,将甘蓝细胞溶质SOD纯化到均一程度。从 10 0 0 g叶片中得到 3 2mg酶 ,酶的比活力达 970 0U/mg蛋白。经鉴定该酶是Cu·Zn SOD。测得其Mr 约为 32 2 0 0 ,亚基Mr 约为 160 0 0。该酶的N 末端为丙氨酸 ,其可见光区与紫外光区的最大吸收峰分别在 680nm和 2 65nm。氨基酸组成分析表明甘蓝细胞溶液质SOD由2 66个氨基酸残基组成 ,而且不含色氨酸。本研究对高等植物细胞溶质SOD的纯化建立了一种行之有效的方法 ,为高等植物SOD性质的比较研究提供了实验依据。

Through a study on purification and properties of superoxide dismutase (SOD) from cabbage plasma , an approach was developed to explore a cheaper source of crude material for preparing SOD The SOD from cabbage plasma has been purified to homogeneity by ammonium sulfate fractionation, Sephadex G 100 gel filtration and DEAE DE52 chromatography The yield of SOD was 3 2 mg per kilogram cabbage leaves, and the specific activity of this enzyme preparation was 9700U/mg protein The purified enzyme was characterized to be a Cu·Zn SOD Electrophoretic analysis indicated that the enzyme contains two homogenous subunits with molecular weight of 16 000 The N terminal of the enzyme is alanine ,and (max in the visible and ultraviolet spectra were at 680 nm and 265 nm, respectively Amino acid component quantitative analysis revealed that this protein was composed of 266 amino acids and lack of tryptophan This study presented an effective approach for SOD purification in higher plant plasma and provided an experimental basis for the comparative study on the higher plants