PURIFICATION AND CHARACTERIZATION OF AN INDUCIBLE DISSIMILATORY TYPE SULFITE REDUCTASE FROM CLOSTRIDIUM-PASTEURIANUM
PURIFICATION AND CHARACTERIZATION OF AN INDUCIBLE DISSIMILATORY TYPE SULFITE REDUCTASE FROM CLOSTRIDIUM-PASTEURIANUM
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DOI：
10.1007/bf00425411
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发表时间：
1984-01-01
影响因子：
2.8
通讯作者：
LAISHLEY, EJ
中科院分区：
文献类型：
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作者：
HARRISON, G;CURLE, C;LAISHLEY, EJ
从C.巴氏杆菌该酶在磷酸盐缓冲液中的最适pH为7.5。由十二烷基硫酸钠凝胶电泳确定还原酶的MW为83，600，具有建议的分子结构：α 2 β 2。其吸收光谱在275 nm处有最大吸收，在370 nm处有宽肩，在585 nm处有很小的吸收峰。没有siroheme发色团被分离出该还原酶。该酶还原下列底物的优先顺序为：NH 2 OH> SeO 32- > NO 22-，还原速率≤50%的其优选底物SO 32-。提出的异化中间体，S3 O 62-或S2 O32-，没有利用这种还原酶; KCN抑制其活性。将底物浓度[SO 32-]从1 μ mol改变到2.5 μ mol，通过将H2吸收与形成的S2-的比率从2.5：1改变到3.1：1来影响酶反应的化学计量。诱导型亚硫酸盐还原酶与铁氧还蛋白相连，铁氧还蛋白可被甲基紫精完全取代或部分被苄基紫精取代。酶的性质和生理特性表明，该酶是一种异化型亚硫酸盐还原酶。
An inducible sulfite reductase was purified from C. pasteurianum. The pH optimum of the enzyme was 7.5 in phosphate buffer. The MW of the reductase was determined to be 83,600 from sodium dodecyl sulfate gel electrophoresis with a proposed molecular structure: .alpha.2.beta.2. Its absorption spectrum showed a maximum at 275 nm, a broad shoulder at 370 nm and a very small absorption maximum at 585 nm. No siroheme chromophore was isolated from this reductase. The enzyme reduced the following substrates in preferential order: NH2OH > SeO32- > NO22- at rates .ltoreq. 50% of its preferred substrate SO32-. The proposed dissimilatory intermediates, S3O62- or S2O32-, were not utilized by this reductase; KCN inhibited its activity. Varying the substrate concentration [SO32-] from 1 to 2.5 .mu.mol affected the stoichiometry of the enzyme reaction by alteration of the ratio of H2 uptake to S2- formed from 2.5:1 to 3.1:1. The inducible sulfite reductase was linked to ferredoxin which could be completely replaced by methyl viologen or partially by benzyl viologen. Some of the enzyme properties and physiological considerations indicated that it was a dissimilatory type sulfite reductase.