Generation of the topa quinone cofactor in bacterial monoamine oxidase by cupric ion‐dependent autooxidation of a specific tyrosyl residue

FEBS Letters

Matsuzaki, Ryuichi¹  Sato, Hidetoshi²  Ozaki, Yukihiro²  Fukui, Toshio¹  Tanizawa, Katsuyuki¹ 

[1] Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567, Japan;Department of Chemistry, School of Science, Kwansei Gakuin University, Nishinomiya, Hyogo 662, Japan

关键词: Monoamine oxidase;    Copper ion;    Topa quinone;    Autogeneration;    topa;    3-(2;    4;    5-trihydroxyphenyl)-l-alanine;    IPTG;    isopropyl-1-thio-β-d-galactopyranoside;   

DOI  :  10.1016/0014-5793(94)00884-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The quinone of 2,4,5-trihydroxyphenylalanine (topa), recently identified as the covalently bound redox cofactor in copper amine oxidases, is encoded by a specific tyrosine codon. To elucidate the mechanism of its formation, the recombinant phenylethylamine oxidase of Arthrobacter globiformis has been overproduced in Escherichia coli and purified in a Cu²⁺-deficient form. The inactive precursor enzyme thus obtained was dramatically activated upon incubation with Cu²⁺, concomitantly with the formation of the topa quinone at the position corresponding to Tyr³⁸², occurring in the tetrapeptide sequence highly conserved in this class of enzymes. The topa quinone was produced only under aerobic conditions, but its formation required no external enzymatic systems. These findings demonstrate the Cu²⁺-dependent autooxidation of a specific tyrosyl residue to generate the topa quinone cofactor.

【 授权许可】

Unknown