Trautwein T, Krauss F, Lottspeich F, Simon H
Institut für Organische Chemie und Biochemie, Technische Universität München, Germany.
Eur J Biochem. 1994 Jun 15;222(3):1025-32. doi: 10.1111/j.1432-1033.1994.tb18954.x.
An oxidoreductase with an extremely broad substrate specificity reducing reversibly 2-oxocarboxylates at the expense of reduced artificial redox mediators to (2R)-hydroxycarboxylates has been purified to a specific activity of up to 1800 mumol.min-1.mg-1 for the reduction of phenylpyruvate. The membrane-bound non-pyridine nucleotide-dependent enzyme appears in the form of various oligomers of the 80-kDa monomer. The isoelectric point is 5.1. Based on a molecular mass of 80 kDa the enzyme contains up to one molybdenum, four iron and four sulphur atoms. After growth on 99Mo-labelled molybdate, enzyme and radioactivity coincided as shown by gel electrophoresis. Permanganate oxidation delivers 0.7 mol pterin-6-carboxylic acid. The molybdenum cofactor is a mononucleotide. The enzyme is inhibited by cyanide. The first 20 amino acids have been determined. The enzyme belongs to the rare group of molybdoenzymes which possess no further prosthetic groups than the iron-sulphur clusters.
一种氧化还原酶已被纯化，其底物特异性极其广泛，能以还原型人工氧化还原介质为代价，将2-氧代羧酸盐可逆地还原为(2R)-羟基羧酸盐，以苯丙酮酸为底物时的比活性高达1800 μmol·min⁻¹·mg⁻¹。这种膜结合的非吡啶核苷酸依赖性酶以80 kDa单体的各种寡聚体形式存在。其等电点为5.1。基于80 kDa的分子量，该酶含有多达一个钼原子、四个铁原子和四个硫原子。在99Mo标记的钼酸盐上生长后，凝胶电泳显示酶与放射性物质重合。高锰酸盐氧化产生0.7 mol蝶呤-6-羧酸。钼辅因子是一种单核苷酸。该酶受氰化物抑制。已测定了前20个氨基酸。该酶属于稀有钼酶组，除了铁硫簇外不具有其他辅基。
