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, such as ethionamide (ETH), isoxyl (ISO) and thiacetazone (TAC), into reactive species. ethionamide + H(+) + NADPH + O2 = ethionamide S-oxide + H2O + NADP(+) Binds 1 FAD per subunit. Is most likely membrane-associated. Repressed by EthR. Deletion of this gene leads to a strong resistance to ETH, ISO and TAC. Belongs to the FAD-binding monooxygenase family.