韭菜叶绿体超氧化物歧化酶纯化及性质研究

经硫酸铵沉淀、ＳｅｐｈａｄｅｘＧ－２００凝胶过滤和ＤＥＡＥ－Ｓｅｐｈａｃｅｌ层析３个步骤将韭菜叶绿体ＳＯＤ纯化到均一程度。鉴定该酶是Ｃｕ．Ｚｎ－ＳＯＤ，测得其分子量约３２０００Ｄ，亚基分子量约为１６２００Ｄ，Ｎ－末端氨基酸为Ａｌａ。该酶在紫外与可见光区的吸收峰分别在２６５ｎｍ和６７５ｎｍ。实验表明该酶热稳定性良好。

Purification and Characterization of Superoxide Dismutase in Leek Chloroplast

A superoxide dismutase from leek chloroplast has been purified to homogeneity by ammonium sulfate fraction, Sephadex G 200 gel filtration and DEAE Sephacel chromatography. The enzyme is a copper/zice superoxide dismutase as assayed by its sensitivity to inhibitors:KCN and H2O2. The molecular weight of the enzyme is about 32 000 daltons as assayed by Sephadex G 200 gel filtration. The enzyme Contains two subunits each of which is about 16 200 daltons as assayed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The N terminal of the enzyme is alanine as tested by dansyl chloride. The enzyme exhibits one absorption maximum in the ultraviolet at 265 nm and another in the visible region at 675 nm. The enzyme has good heat stability. 