title: The oxidation of cyclic sulfides by tetramethyldioxetane and the isobutanal/O2/peroxidase system: oxygen transfer versus electron transfer.
abstract: The oxidation of chlorpromazine (CPZ) by tetramethyldioxetane (TMD) and isobutanal (IBAL)/O2/horseradish peroxidase (HRP) system was investigated. The reaction with TMD proved to be of the oxygen transfer type, generating chlorpromazine-5-oxide (CPZO) and tetramethylethylene-oxide, and not by single-electron transfer, as previously reported. In contrast, the reaction of CPZ with IBAL/O2/HRP leads to formation of chlorpromazine cation radical, through reaction with active intermediates Compound I and II, following its dismutation and hydrolysis to CPZO. For comparison, 10-methylphenothiazine was also tested. Despite the fact that both systems are known to generate oxidizing triplet acetone, this species does not participate in the oxidation path in either case.
authors.affiliation: Departamento de Bioquímica, Universidade de São Paulo, Brazil.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bechara
authors.forename: L H
authors.initials: LH
authors.lastname: Catalani
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D002746:Chlorpromazine / Q000378:metabolism; D004579:Electron Transport; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D009195:Peroxidase / Q000494:pharmacology; D013440:Sulfides / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D013440:Sulfides; C017439:isobutyraldehyde; D009195:Peroxidase; D010100:Oxygen; D002746:Chlorpromazine