Kinetics and spectroscopic evidence that the Cu(I)-semiquinone intermediate reduces molecular oxygen in the oxidative half-reaction of Arthrobacter globiformis amine oxidase.

ABSTRACT: The role of copper during the reoxidation of substrate-reduced amine oxidases by O(2) has not yet been definitively established. Both outer-sphere and inner-sphere pathways for the reduction of O(2) to H(2)O(2) have been proposed. A key step in the inner-sphere mechanism is the reaction of O(2) directly with the Cu(I) center of a Cu(I)-semiquinone intermediate. To thoroughly examine this possibility, we have measured the spectral changes associated with single-turnover reoxidation by O(2) of substrate-reduced Arthrobacter globiformis amine oxidase (AGAO) under a wide range of conditions. We have previously demonstrated that the internal electron-transfer reaction [Cu(II)-TPQ(AMQ) --> Cu(I)-TPQ(SQ)] (where TPQ(AMQ) is the aminoquinol form of reduced TPQ and TPQ(SQ) is the semiquinone form)

SUBMITTER: Shepard EM 

PROVIDER: S-EPMC2757038 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature