Characterization of the brain family of aromatic amine N- acetyltransferases

Arylamine and arylalkylamine N-acetyltransferase activities in the rat brain were isolated and partially characterized. A total of four N- acetyltransferase activities were identified using a combination of three separation procedures, ammonium sulfate fractionation, methotrexate affinity chromatography, and size-exclusion HPLC. Two of the N-acetyltransferase activities demonstrated preference for arylamines and differential sensitivity to inhibition by methotrexate. The other two activities were characterized as arylalkylamine N-acetyltransferase based on their preference for arylalkylamines such as serotonin and tryptamine. Potential functions of these enzyme activities in the brain are discussed.