Jones J B, Stadtman T C
J Biol Chem. 1980 Feb 10;255(3):1049-53.
The formate-dependent reduction of NADP+ by extracts of Methanococcus vannielii is catalyzed by a coupled system consisting of formate dehydrogenase, a 5-deazaflavin cofactor, and 5-deazaflavin-dependent NADP+ reductase. All three components were purified from crude extracts of M. vannielii. Recombination of these components reconstituted the formate-NADP+ oxidoreductase system. The formate dehydrogenase also can utilize FAD, FMN, and a number of artificial dyes as electron acceptors, but these do not replace the 5-deazaflavin cofactor in the coupled enzyme system. The reduced form of 5-deazaflavin binds readily to the NADP+ reductase apoprotein and is not dissociated by ammonium sulfate treatment at neutral pH under anaerobic conditions. This electron transfer cofactor from M. vannielii is identical in many of its properties to the 5-deazaflavin isolated from other methane-producing bacteria.
瓦氏甲烷球菌提取物以甲酸为依赖将NADP⁺还原的反应由一个偶联系统催化，该系统由甲酸脱氢酶、一种5-脱氮黄素辅因子和5-脱氮黄素依赖的NADP⁺还原酶组成。所有这三种成分均从瓦氏甲烷球菌的粗提取物中纯化得到。这些成分的重组重构了甲酸-NADP⁺氧化还原酶系统。甲酸脱氢酶还可以利用FAD、FMN和多种人工染料作为电子受体，但在偶联酶系统中这些不能替代5-脱氮黄素辅因子。5-脱氮黄素的还原形式很容易与NADP⁺还原酶脱辅基蛋白结合，并且在厌氧条件下于中性pH值时不会因硫酸铵处理而解离。这种来自瓦氏甲烷球菌的电子传递辅因子在许多性质上与从其他产甲烷细菌中分离出的5-脱氮黄素相同。
