Inactivation of hamster monomorphic N-acetyltransferase by vinyl fluorenyl ketone

Arylamine N-acetyltransferases (NATs) are cytosolic enzymes that play important roles in the detoxification and activation of xenobiotic arylamines and their metabolites. Vinyl fluorenyl ketone (VFK) is a selective and potent active site-directed irreversible inhibitor of rat liver monomorphic NAT. The present study demonstrated that VFK is an active site-directed affinity label for hamster liver monomorphic NAT, but is a much less effective inactivator of the polymorphic N-acetyltransferase isozyme. The potency, irreversibility and selectivity of VFK make it a potentially valuable tool for characterization of NATs that exhibit acetyl donor specificity similar to that of hamster monomorphic NAT.