Roh J H, Takenaka Y, Suzuki H, Yamamoto K, Kumagai H
Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
Biochem Biophys Res Commun. 1995 Jul 26;212(3):1107-14. doi: 10.1006/bbrc.1995.2083.
Copper-containing monoamine oxidase (EC 1.4.3.6) from Escherichia coli is a periplasmic enzyme containing topa quinone in addition to divalent copper as a cofactor. The amino acid sequence of E. coli monoamine oxidase was compared to several cloned amine oxidase genes and five well-conserved histidine residues were found. Site-directed mutagenesis studies were performed to determine which histidine residue serves as the binding ligand to the copper. Enzyme activity, absorption spectrum, and atomic absorption spectrophotometry of the mutant enzymes indicated that histidines 470, 554, and 556 are the copper binding ligands. The absorption spectra of phenylhydrazine derivatives suggested that copper is necessary for topa quinone formation.
来自大肠杆菌的含铜单胺氧化酶（EC 1.4.3.6）是一种周质酶，除了二价铜作为辅因子外，还含有对苯二酚醌。将大肠杆菌单胺氧化酶的氨基酸序列与几个克隆的胺氧化酶基因进行了比较，发现了五个保守性良好的组氨酸残基。进行了定点诱变研究，以确定哪个组氨酸残基作为铜的结合配体。突变酶的酶活性、吸收光谱和原子吸收分光光度法表明，组氨酸470、554和556是铜结合配体。苯肼衍生物的吸收光谱表明，铜对于对苯二酚醌的形成是必需的。
