RESOLUTION OF DISTINCT SELENIUM-CONTAINING FORMATE DEHYDROGENASES FROM ESCHERICHIA-COLI
RESOLUTION OF DISTINCT SELENIUM-CONTAINING FORMATE DEHYDROGENASES FROM ESCHERICHIA-COLI
复制标题
DOI：
10.1128/jb.145.3.1317-1324.1981
复制
发表时间：
1981-01-01
影响因子：
3.2
通讯作者：
DEMOSS, JA
中科院分区：
文献类型：
--
作者：
COX, JC;EDWARDS, ES;DEMOSS, JA
甲酸脱氢酶是厌氧E.大肠杆菌中分离出2种可区分的酶。一个，这是诱导硝酸还原酶作为甲酸-硝酸还原酶途径的一个组成部分，使用吩嗪硫酸甲酯（PMS）优先于苄基紫精（BV）作为人工电子受体，似乎是专门的膜结合。第二甲酸脱氢酶，这是诱导的甲酸氢解酶途径的一个组成部分，似乎存在作为一种膜结合的形式和作为一种细胞质酶;细胞质的活性完全解决从PMS-连接的活性蔗糖梯度。当E.大肠杆菌在75 Se-亚硒酸盐存在下生长，75 Se-亚硒酸盐是一种道尔顿为110，000的硒肽，先前显示为PMS-连接酶的组分，其被诱导并被该活性抑制。相反，一个80，000道尔顿的硒肽被诱导和抑制的BV-连接的活性，并表现出类似的分布BV-连接的甲酸脱氢酶在细胞组分和蔗糖梯度。这2种甲酸酯酶在人工电子受体特异性、细胞定位和硒蛋白组分大小上有明显区别。
Formate dehydrogenase, a component activity of 2 alternative electron transport pathways in anaerobic E. coli was resolved as 2 distinguishable enzymes. One, which was induced with nitrate reductase as a component of the formate-nitrate reductase pathway, used phenazine methosulfate (PMS) in preference to benzyl viologen (BV) as an artificial electron acceptor and appeared to be exclusively membrane-bound. A 2nd formate dehydrogenase, which was induced as a component of the formate hydrogenlyase pathway, appeared to exist both as a membrane-bound form and as a cytoplasmic enzyme; the cytoplasmic activity was resolved completely from the PMS-linked activity on a sucrose gradient. When E. coli was grown in the presence of 75Se-selenite, a 110,000 dalton selenopeptide, previously shown to be a component of the PMS-linked enzyme, was induced and repressed with this activity. In contrast, an 80,000 dalton selenopeptide was induced and repressed with the BV-linked activity and exhibited a distribution similar to the BV-linked formate dehydrogenase in cell fractions and in sucrose gradients. The 2 formate dehydrogenases are apparently distinguishable on the basis of their artificial electron acceptor specificity, their cellular localization and the size of their respective selenoprotein components.