Sulphide-linked Nitrite Reductase from Thiobacillus denitrificans with Cytochrome Oxidase Activity: Purification and Properties
Sulphide-linked Nitrite Reductase from Thiobacillus denitrificans with Cytochrome Oxidase Activity: Purification and Properties
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来自脱氮硫杆菌的具有细胞色素氧化酶活性的硫连接亚硝酸盐还原酶：纯化和性质
DOI：
10.1099/00221287-106-1-119
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发表时间：
1978
期刊：
影响因子：
1.5
通讯作者：
D. Nicholas
中科院分区：
文献类型：
--
作者：
V. Sawhney;D. Nicholas
对脱氮硫杆菌的膜结合硫化物亚硝酸还原酶进行了溶解，进一步纯化后对其性质进行了研究。纯化后的酶，摩尔比。WT 120 000，含有细胞色素c和d，比例为1：1。这两种细胞色素都被硫化物还原，然后用亚硝酸盐或空气重新氧化。经亚硝酸根氧化后，在572 nm处出现一吸收峰。酶的硫化物还原动力学表明，细胞色素c在细胞色素d之前被还原，细胞色素d的氧化还原电位比细胞色素c的氧化还原电位高22 mV，经十二烷基硫酸钠处理后，细胞色素c和d从纯化的酶中解离。纯化的亚硝酸还原酶也具有细胞色素氧化酶活性，这两种活性都被脱氮毛霉的细胞色素c-551所激活。还原的细胞色素c-551是以亚硝酸盐或空气为末端电子受体的纯化酶的有效电子供体。细胞色素c-554(也是从脱氮毛滴虫中分离出来的)和哺乳动物细胞色素c都不能作为酶的还原剂。纯化的硫化物连接亚硝酸盐还原酶可将NO和N2O还原为亚硝酸盐的产物。
A membrane-bound, sulphide-linked nitrite reductase from Thiobacillus denitrificans was solubilized and after further purification its properties were examined. The purified enzyme, mol. wt 120 000, contained cytochromes c and d in the ratio of 1:1. Both cytochromes were reduced by sulphide and re-oxidized with nitrite or air. Oxidation by nitrite resulted in the appearance of an absorption peak at 572 nm. The kinetics of the reduction of the enzyme with sulphide indicated that cytochrome c was reduced before cytochrome d. The redox potential of cytochrome d was 22 mV more positive than that of cytochrome c. Cytochromes c and d were dissociated from the purified enzyme by treatment with sodium dodecyl sulphate. The purified nitrite reductase also had cytochrome oxidase activity and both the activities were stimulated by cytochrome c-551 isolated from T. denitrificans. Reduced cytochrome c-551 was an effective electron donor for the purified enzyme with either nitrite or air as the terminal electron acceptor. Neither cytochrome c-554 (also isolated from T. denitrificans) nor mammalian cytochrome c was effective as reductant for the enzyme. NO and N2O were identified as the products of nitrite reduction by the purified sulphide-linked nitrite reductase.