FEATURES

FAMILY

DESCRIPTION

Also known as ETHA_MYCTU, ethA, etaA. Monooxygenase able to convert a wide range of ketones to the corresponding esters or lactones via a Baeyer-Villiger oxidation reaction. Can act on long-chain aliphatic ketones (2-hexanone to 2-dodecanone) and on aromatic ketones (phenylacetone and benzylacetone). Is also able to catalyze enantioselective sulfoxidation of methyl-p-tolylsulfide. In vivo, likely functions as a BVMO, but the exact nature of the physiological substrate(s) remains to be established., Is responsible for the activation of several thiocarbamide-containing pro-drugs into cytotoxic species. Thus, catalyzes the oxidation of the antitubercular pro-drug ethionamide (ETH) to the corresponding sulfoxide, which is further oxidized by EthA to 2-ethyl-4-amidopyridine, presumably via the unstable doubly oxidized sulfinic acid intermediate; the final metabolite 2-ethyl-4-amidopyridine has no antitubercular activity, so the cytotoxic species is a metabolite intermediate formed by EthA. Also oxidizes thiacetazone (TAC), thiobenzamide, and isothionicotinamide and therefore is probably responsible, as suggested by the observation of crossover resistance, for the oxidative activation of these other thioamide antitubercular drugs. Exists as a mixture of relatively large homooligomers ranging from 200 to 600 kDa.

EXTERNAL LINKS

ethA

FAD-containing monooxygenase EthA

ethA

Molecular Synopsis