title: Reversible inactivation of bovine plasma amine oxidase by cysteamine and related analogs.
abstract: Cysteamine (1) was reported many years ago to reversibly inhibit lentil seedling amine oxidase, through the formation of a complex with thioacetaldehyde, the turnover product of 1. Herein, cysteamine (1) and its analogs 2-(methylamino)ethanethiol (3) and 3-aminopropanethiol (6) were found to be reversible inhibitors of bovine plasma amine oxidase (BPAO), but 2-(methylthio)ethylamine (7) was determined to be a weak irreversible inhibitor of BPAO. Based on our results, indicating the necessity of a sulfhydryl-amine for reversible inactivation of BPAO, the failure of inhibited BPAO to recover activity after gel filtration, the first-order kinetics of activity recovery upon dialysis, and 2,4,6-trihydroxyphenylalanine quinine (TPQ) cofactor transformation which indicated from the results of phenylhydrazine titration and substrate protection, we propose a mechanism for the reversible inactivation of BPAO by 1 involving the formation of a cofactor adduct, thiazolidine, between BPAO and 1.
authors.affiliation: Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea. hbj@kw.ac.kr
authors.forename: Heung Bae
authors.initials: HB
authors.lastname: Jeon
authors.forename: Yujin
authors.initials: Y
authors.lastname: Jang
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors* / Q000097:blood; D000818:Animals; D002417:Cattle; D003543:Cysteamine / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D003543:Cysteamine; D006631:Amine Oxidase (Copper-Containing)