Molecular properties of fumarate reductase isolated from the cytoplasmic membrane of Escherichia coli.
Molecular properties of fumarate reductase isolated from the cytoplasmic membrane of Escherichia coli.
复制标题
从大肠杆菌细胞质膜分离的富马酸还原酶的分子特性。
DOI：
10.1139/o82-101
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
J. Weiner
中科院分区：
文献类型：
--
作者：
J. Robinson;J. Weiner
富马酸还原酶是从大肠杆菌细胞质膜上纯化的一种酶，它与双功能试剂二甲基磺酰亚胺交联，以1：1摩尔比存在于分子量为69000和25000的多肽的α-β二聚体中。该蛋白的S_(20)，w=7.67S，D_(20)，w=6.5×10~(-7)cm~2/S。纯化的酶含有4-5摩尔的非血红素铁和4-5摩尔的酸不稳定硫。由于存在Fe-S中心和8α[N-3]组氨酸，可见吸收光谱在400~470 nm处有一个宽峰。5，5‘-二硫代二(2-硝基)苯甲酸、对氯汞苯甲酸和碘代乙酰胺容易抑制富马酸还原酶的活性。用5，5‘-二硫代-(2-硝基)苯甲酸进行了巯基修饰，这是酶活性的函数。活性需要一个半胱氨酸残基，这个必需的巯基位于69,000个道尔顿亚基上。富马酸还原酶的氨基酸组成与牛心线粒体和红螺菌的琥珀酸脱氢酶相似。
Fumarate reductase, purified from the cytoplasmic membrane of Escherichia coli, has been cross-linked with the bifunctional reagent dimethylsuberimidate and shown to exist as an alpha beta dimer of polypeptides of molecular weights 69,000 and 25,000 in a 1:1 molar ratio. The protein has an s20,w of 7.67S and a D20,w of 6.5 X 10(-7) cm2/s. The purified enzyme contained 4-5 mol of nonheme iron and 4-5 mol of acid labile sulfur while the visible absorption spectrum showed a broad peak between 400 and 470 nm owing to the presence of an Fe-S centre and 8 alpha[N-3]histidyl FAD. Fumarate reductase activity was readily inhibited by the sulfhydryl reagents 5,5'-dithiobis-(2-nitrobenzoic acid), p-chloromercuribenzoate, and iodoacetamide. Using 5,5'-dithiobis-(2-nitrobenzoic acid) sulfhydryl group modification was followed as a function of enzyme activity. A single cysteine residue was shown to be required for activity and this essential sulfhydryl group was located in the 69,000 dalton subunit. The amino acid composition of E. coli fumarate reductase was similar to the succinate dehydrogenases from beef heart mitochondrion and Rhodospirillum rubrum.