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Generation of the topa quinone cofactor in bacterial monoamine oxidase by cupric ion‐dependent autooxidation of a specific tyrosyl residue
Author(s) -
Matsuzaki Ryuichi,
Fukui Toshio,
Sato Hidetoshi,
Ozaki Yukihiro,
Tanizawa Katsuyuki
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00884-1
Subject(s) - quinone , cofactor , chemistry , tyrosine , biochemistry , enzyme , autoxidation , tetrapeptide , residue (chemistry) , escherichia coli , stereochemistry , peptide , gene
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 Cu 2+ ‐deficient form. The inactive precursor enzyme thus obtained was dramatically activated upon incubation with Cu 2+ , concomitantly with the formation of the topa quinone at the position corresponding to Tyr 382 , 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 Cu 2+ ‐dependent autooxidation of a specific tyrosyl residue to generate the topa quinone cofactor.