1.14.13.230 Butanoate incubation of alkane-grown cells with butanoate or propanoate leads to irreversible time- and O2-dependent loss of butane monooxygenase activity 683 1.14.13.230 propanoate 10 mM, 41% residual activity. Incubation of alkane-grown cells with butanoate or propanoate leads to irreversible time- and O2-dependent loss of butane monooxygenase activity. Propanoate-dependent inactivation involves interaction with the catalytic site. Butane monooxygenase is protected from propanoate-dependent inactivation by the presence of its natural substrate, butane 949