Van Ophem P W, Van Beeumen J, Duine J A
Department of Microbiology and Enzymology, Delft University of Technology, The Netherlands.
Eur J Biochem. 1993 Mar 15;212(3):819-26. doi: 10.1111/j.1432-1033.1993.tb17723.x.
Extracts of Gram-positive bacteria like Rhodococcus rhodochrous, Rhodococcus erythropolis and Amycolatopsis methanolica, but not those of several Gram-negative ones, showed dehydrogenase activity for ethanol as well as for methanol when 4-nitroso-N,N-dimethylaniline (NDMA) was used as electron acceptor. Chromatography of extracts of the first two organisms revealed one activity for both substrates, that of A. methanolica two activities, one of which is able to oxidize methanol and has been purified (Bystrykh, L.V., Govorukhina, N.I., van Ophem, P.W., Hektor, H.J., Dijkhuizen, L. and Duine, J.A., unpublished results). The other, indicated as NDMA-dependent alcohol dehydrogenase (NDMA-ADH), was purified to homogeneity. It is a trimeric enzyme consisting of subunits of 39 kDa and one firmly bound NAD as cofactor. Although NDMA-ADH shows structural similarity with the long-chain, zinc-containing, NAD(P)-dependent alcohol dehydrogenases with respect to the N-terminal sequence up to residue 41 (56% identity with horse liver alcohol dehydrogenase), the enzymes are catalytically different since NDMA-ADH is unable to use NAD(P)(H) as a coenzyme and NAD(P)-dependent alcohol dehydrogenases are inactive with NDMA (in the absence of NAD). Comparison of the NDMA-ADH properties with those of the methanol-oxidizing enzyme of A. methanolica, Mycobacterium gastri and Bacillus methanolica C1, and formaldehyde dismutase of Pseudomonas putida F61 revealed large differences in structural as well as catalytic properties, in spite of the fact that all are nicotinoproteins [enzymes which have bound NAD(P) as a cofactor]. It is concluded, therefore, that NDMA-ADH is a novel type of nicotinoprotein alcohol dehydrogenase.
当使用4-亚硝基-N,N-二甲基苯胺（NDMA）作为电子受体时，红平红球菌、红球菌和甲醇拟无枝酸菌等革兰氏阳性菌的提取物表现出对乙醇和甲醇的脱氢酶活性，而几种革兰氏阴性菌的提取物则没有这种活性。对前两种微生物提取物的色谱分析显示，两种底物具有一种活性，甲醇拟无枝酸菌有两种活性，其中一种能够氧化甲醇且已被纯化（Bystrykh, L.V., Govorukhina, N.I., van Ophem, P.W., Hektor, H.J., Dijkhuizen, L. 和 Duine, J.A.，未发表的结果）。另一种被称为NDMA依赖性醇脱氢酶（NDMA-ADH）的酶被纯化至同质。它是一种三聚体酶，由39 kDa的亚基和一个紧密结合的NAD作为辅因子组成。尽管NDMA-ADH在N端序列直至第41位残基方面与长链、含锌、NAD(P)依赖性醇脱氢酶具有结构相似性（与马肝醇脱氢酶有56%的同一性），但这些酶在催化方面有所不同，因为NDMA-ADH不能使用NAD(P)(H)作为辅酶，而NAD(P)依赖性醇脱氢酶对NDMA无活性（在没有NAD的情况下）。将NDMA-ADH的性质与甲醇拟无枝酸菌、胃分枝杆菌和甲醇芽孢杆菌C1的甲醇氧化酶以及恶臭假单胞菌F61的甲醛歧化酶的性质进行比较，结果显示，尽管它们都是烟酰胺蛋白[以结合的NAD(P)作为辅因子的酶]，但在结构和催化性质上存在很大差异。因此得出结论，NDMA-ADH是一种新型的烟酰胺蛋白醇脱氢酶。
