Characterization of the active site of Arthrobacter P1 methylamine oxidase: evidence for copper-quinone interactions

Arthrobacter P1 methylamine oxidase is the first prokaryotic copper-containing amine oxidase to be discovered. Our initial characterization of the active-site structure and reactivity of methylamine oxidase is described herein. Spectroscopic studies, using a variety of techniques, of the resting (ox...

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Bibliographic Details
Published in:Journal of the American Chemical Society 1990-03, Vol.112 (7), p.2782-2789
Main Authors: Dooley, David M, McIntire, William S, McGuirl, Michele A, Cote, Cheryl E, Bates, Jennifer L
Format: Article
Language:English
Subjects:
active sites
Bacteriology
Biological and medical sciences
C.D
copper
electron transfer
Fundamental and applied biological sciences. Psychology
Metabolism. Enzymes
methylamine oxidase
Microbiology
quinone
spectroscopy
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Summary:Arthrobacter P1 methylamine oxidase is the first prokaryotic copper-containing amine oxidase to be discovered. Our initial characterization of the active-site structure and reactivity of methylamine oxidase is described herein. Spectroscopic studies, using a variety of techniques, of the resting (oxidized), substrate-reduced, and copper-depleted forms of methylamine oxidase have been carried out. Inhibitor binding to the copper ions and to the organic cofactor has also been investigated. Both ammonia and phenylhydrazine bind to the organic cofactor in the enzyme. Ammonia binds reversibly with K sub(D) = 8.3 plus or minus 0.8 mM at pH 8.51; it also inhibits the enzyme, in part by significantly decreasing the methylamine oxidase reduction rate by substrates. Electron transfer between the reduced quinone and Cu(II) is shown to occur in the presence of ligands that stabilize Cu(I), generating a semiquinone and Cu(I).
ISSN:0002-7863
1520-5126
DOI:10.1021/ja00163a047