Flavin-containing monooxygenase activity in the gumboot chitonCryptochiton stelleri

Flavin-containing monooxygenase (FMO) activity was observed in microsomes from the digestive gland of the gumboot chitonCryptochiton stelleri. Digestive-gland microsomal oxygen uptake was initiated after the addition of N,N-dimethylaniline (DMA), methimazole, phenylhydrazine (PH), 2-aminofluorene (2-AF), or 1,1-dimethylhydrazine (DMH) to the incubations. The pH optimum for 2-AF dependent oxygen uptake was 8.4 and required NADPH. The formation of DMA N-oxide and the oxidation of methimazole was measured and confirmed the presence of FMO activity in this tissue.