Van Ophem P W, Bystrykh L V, Duine J A
Department of Microbiology and Enzymology, Delft University of Technology, The Netherlands.
Eur J Biochem. 1992 Jun 1;206(2):519-25. doi: 10.1111/j.1432-1033.1992.tb16955.x.
Cell-free extracts of methanol-grown Amycolatopsis methanolica contain dye-linked dehydrogenase activities for formate and methyl formate. Fractionation of the extracts revealed that the (unstable) activity for formate resides in membrane particles, while that for methyl formate belongs to a soluble enzyme that was purified and characterized. The enzyme, indicated as formate-ester dehydrogenase, appeared to be a molybdoprotein (4 Fe, 3 or 4 S, 1 Mo and 1 FAD were found for each enzyme molecule), with a molecular mass of 186 kDa and consisting of two subunits of equal size. Product identification suggests that the formate moiety in the ester becomes hydroxylated to a carbonate group after which the unstable alkyl carbonate decomposes into CO2 and the alcohol moiety. Based on structural and catalytic characteristics, the enzyme appears to be very similar to an enzyme isolated from Comamonas testosteroni [Poels, P. A., Groen, B. W. & Duine, J. A. (1987) Eur. J. Biochem. 166, 575-579] which was at that time considered to be an aldehyde dehydrogenase. Formate-ester dehydrogenase activity appeared to be present in several other bacteria. Possible roles for the A. methanolica enzyme in C1 dissimilation (oxidation of methyl formate to methanol and CO2 or a factor-formate adduct to factor plus CO2) or in general aldehyde oxidation, are discussed.
甲醇培养的甲醇拟无枝酸菌的无细胞提取物含有与甲酸和甲酸甲酯相关的染料偶联脱氢酶活性。提取物的分级分离表明，（不稳定的）甲酸活性存在于膜颗粒中，而甲酸甲酯的活性则属于一种已纯化和表征的可溶性酶。该酶被称为甲酸酯脱氢酶，似乎是一种钼蛋白（每个酶分子含有4个铁原子、3或4个硫原子、1个钼原子和1个黄素腺嘌呤二核苷酸），分子量为186 kDa，由两个大小相等的亚基组成。产物鉴定表明，酯中的甲酸部分被羟基化为碳酸基团，之后不稳定的碳酸烷基酯分解为二氧化碳和醇部分。基于结构和催化特性，该酶似乎与从睾丸丛毛单胞菌中分离出的一种酶非常相似[Poels, P. A., Groen, B. W. & Duine, J. A. (1987) Eur. J. Biochem. 166, 575 - 579]，当时该酶被认为是一种醛脱氢酶。甲酸酯脱氢酶活性似乎存在于其他几种细菌中。本文讨论了甲醇拟无枝酸菌的这种酶在C1异化作用（将甲酸甲酯氧化为甲醇和二氧化碳或因子 - 甲酸加合物氧化为因子和二氧化碳）或一般醛氧化中的可能作用。
