Possible model reaction for some amine oxidases.  Kinetics and mechanism of the copper(II)-catalyzed autoxidation of some diaminouracils

Al-Arab, Mohammad M.; Hamilton, Gordon A.

doi:10.1021/ja00279a051

Cited by 16 publications

(1 citation statement)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the latter case, competitive or additional 02 binding to Cu2+ seems unlikely to occur. Moreover, copper-catalysed reactions with 02 usually involve Cu+ intermediates (Al-Arab & Hamilton, 1986), which were never detected either in the catalytic -cycle of the pig plasma amine oxidase (Grant et at., 1978) or in the present study. For these reasons, in Scheme 1 the reaction with 02 is tentatively proposed to procede via a hydroperoxy intermediate.…”

Section: Reaction Mechanismmentioning

confidence: 99%

Benzylhydrazine as a pseudo-substrate of bovine serum amine oxidase

Morpurgo¹,

Agostinelli²,

Muccigrosso³

et al. 1989

Biochemical Journal

View full text Add to dashboard Cite

Bovine serum amine oxidase is inhibited by benzylhydrazine (BHy), but recovers full activity after a few hours incubation [Hucko-Haas & Reed (1970) Biochem. Biophys. Res. Commun. 38, 396-400]. The first phase of the process, requiring about 15 min, was found to consist of a mechanism-based hydrazine-transfer reaction leading to formation of the hydrazine-bound enzyme, benzaldehyde and H2O2. At variance with the enzymic process, the reaction with O2 preceded the benzaldehyde release. Two reaction intermediates could be characterized by optical spectroscopy and were assigned as the azo derivative and the benzaldehyde hydrazone, the latter one probably being involved in the reaction with O2. No reduction of Cu was detected at any stage. The hydrazine adduct could also be obtained by stoichiometric reaction of hydrazine with the native enzyme. The decay of this species occurred in about 8 h and was not studied in detail. The Cu-binding inhibitor NN-diethyldithiocarbamate affected the BHy reaction by stabilizing the benzaldehyde hydrazone form as against the azo derivative and the reaction with O2. However, under these same conditions the initial spectroscopic properties of the diethyldithiocarbamate adduct were recovered if the oxidase was left overnight. The reaction with O2 was abolished only upon removal of at least one Cu atom from the enzyme. On the basis of the failure to detect any change of Cu redox state and the enzyme behaviour in the presence of inhibitors, a reaction mechanism involving the formation of a hydroperoxy intermediate, as in the FAD-containing enzymes, is tentatively proposed.

show abstract

Section: Reaction Mechanismmentioning

confidence: 99%