N-acylation of tyramines: purification and characterization of an arylamine N-acetyltransferase from rat brain and liver.

The N-acylation of tyramine isomers and other biogenic amines has been studied. The liver exhibits the highest activity towards tyramines, while the brain exhibits a low but significant activity. In the brain, tyramine N-acylation activity was heterogenously distributed. The arylamine N-acetyltransferase has been partially purified from both rat liver and brain, the two enzymes being quite similar with respect to their chromatographic properties, optimal pH requirement (pH 7.8), and their kinetic parameters. The product N-acetyltyramine is not oxidized by liver amidohydrolase or monoamine oxidase.