蚕豆种子超氧物歧化酶的纯化及性质

PURIFICATION AND CHARACTERIZATION OF SUPEROXIDE DISMUTASE FROM BROAD BEAN SEEDS

摘要:

蚕豆种子粗提液经乙醇－氯仿混合物处理、丙酮沉淀、ＤＥＡＥ－纤维素层析和Ｓｅｐｈａｒｏｓｅ６Ｂ层析，获得比活性为２８５２单位ｍｇ－１蛋白的超氧物歧化酶．经聚丙烯酰胺凝胶电泳证明酶已纯化到均一程度．该酶对ＫＣＮ和Ｈ２Ｏ２敏感，说明它为Ｃｕ，Ｚｎ－ＳＯＤ．酶分子量和亚基分子量分别为３１０００和１４４００，说明它是由两个相同亚基组成。该酶在７０℃以下和在ｐＨ５—９条件下稳定．紫外区最大吸收峰为２７３．５ｎｍ。

Abstract:

Cupper and zinc-containing superoxide dismutase from broad beau(Vicia faba) seeds was purified to homogeneity by the steps of crude extract, chloroform-ethanol treatment, aceton precipitation, DEAE-cellulose chromatography and Sepharose 6B chromatography. The purified enzyme had a specific activity of 2852 units mg-1 protein. Its activity was strongly inhibited by KCN and H2O2. Its molecular weight and subunit molecular weight were 31000 and 14400 respectively, which indicated that the enzyme was composed of two identical subunits. The enzyme was stable to heat below 70 ℃ and to pH at range of 5 -9, and exhibited maximum ultraviolet absorption at 273.5um.