Function
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.
Sequence
MTEHLDVVIVGAGISGVSAAWHLQDRCPTKSYAILEKRESMGGTWDLFRYPGIRSDSDMYTLGFRFRPWTGRQAIADGKPILEYVKSTAAMYGIDRHIRFHHKVISADWSTAENRWTVHIQSHGTLSALTCEFLFLCSGYYNYDEGYSPRFAGSEDFVGPIIHPQHWPEDLDYDAKNIVVIGSGATAVTLVPALADSGAKHVTMLQRSPTYIVSQPDRDGIAEKLNRWLPETMAYTAVRWKNVLRQAAVYSACQKWPRRMRKMFLSLIQRQLPEGYDVRKHFGPHYNPWDQRLCLVPNGDLFRAIRHGKVEVVTDTIERFTATGIRLNSGRELPADIIITATGLNLQLFGGATATIDGQQVDITTTMAYKGMMLSGIPNMAYTVGYTNASWTLKADLVSEFVCRLLNYMDDNGFDTVVVERPGSDVEERPFMEFTPGYVLRSLDELPKQGSRTPWRLNQNYLRDIRLIRRGKIDDEGLRFAKRPAPVGV