烟草头孢霉汞还原酶特性的研究

PROPERTIES OF MERCURIC REDUCTASE OF CEPHALOSPORIUM TABACINUM

经检测,抗汞真菌烟草头孢霉(Cephalosporium tabacinum)F2菌株中具有汞还原酶活性。该酶是一种胞内酶,需 NADH 作为电子供体,催化 Hg^(2+)还原成为元素汞(Hg^(?))。该酶促反应还需硫氢基化合物,反应最适温度为30℃,最适 pH 范围为7.0—8.0。在25—30℃保温40分钟或在 pH7.0保温2小时,酶活力均是稳定的。金属离子 Ag^+,Co^(2+),Cu^(2+),Zn^(2+),Mn^(2+)和 Ni^(2+)在浓度为0.2—1.0mmol/L 的范围内,对酶活力有不同程度的抑制作用,一定浓度的乙酸苯汞和铁氰化钾对酶活力也有部分抑制作用。

The mercuric reductase was detected in the Cephalosporium tabacinum F2.The enzyme,which was an intracellular enzyme,catalyzed the reduction of mercuric ions to elementalmercury,which required NADH as electron donor and added thiol compound.The optimumtemperature and pH of the enzymatic reaction were 30℃ and 7.0—8.0,respectively.Theenzyme activity was stable in the range of 25—30℃ for 40 rain and stable at pH 7.0 for 2h.Metal ions,such as Ag^+,Co^(2+);Gu^(2+),Zn^(2+),Mn^(2+),Ni^(2+) showed different degree inhibitoryeffect on the enzyme activity,other compounds,such as phenylmercuric acetate and potassiumferricyanide,also partially inhibited the enzyme activity.