豌豆种子超氧化物歧化酶的纯化及性质

PURIFICATION AND CHARACTERIZATION OF SUPEROXIDE DISMUTQSE FROM PEA SEEDS

从豌豆种子提纯了超氧化物歧化酶（ＳＯＤ），纯酶比活性为７８４４×１０３Ｕ／ｇ。该酶受ＫＣＮ和Ｈ２ｐ２的强烈抑制，不受乙醇一氯仿混合液影响，说明为Ｃｕ、Ｚｎ－ＳＯＤ。酶分子量和亚基分子量分别为３２１００×和１４４００，表明该酶是由两个相同亚基组成。该酶在７０℃以下和ｐＨ５．０～１１．０范围内较稳定，紫外区最大吸收波长为２５９ｎｍ。

Cupper and zinc-containing superoxide dismutase was purified from pea seeds tohomogeneity by the steps of cnlde extract,chloroform -ethanol treatmtnt,acetonepredpitation,and chromatography with DEAE-eellulose,DEAE-SepharDse and Sepharose 6Bcolumns.The homogenous enzyme had a specific activity of 7 844 U/mg protein,and ex -hbited maximum ultraviolet absorption at 259 nm.Its activity was strongly inhibited by KCNand H2O2. Its molecular weight and subunit molecular weight were 32 100 and 1 4 400respectively,which indicated that the enzyme was composed of two identical subunits;The purified enzyme was stable to heat below 70℃ and at pH 5～11.