Purification and partial characterization of chicken liver acetyl coenzyme A: arylamine N-acetyltransferase.

Arylamine acetyltransferase (EC 2.3.1.5) was purified 120-fold from chicken liver. The enzyme showed a rise in activity from pH 6.5 to 7.7 followed by a constant activity to about pH 8.6. The relative molecular weight of the enzyme was about 34,000. The apparent Km for acetyl-CoA was 13 microM with 4-nitroaniline as acetyl-acceptor. CoA was a noncompetitive inhibitor relative to acetyl-CoA with apparent Ki value of 110 microM. With 4-methylaniline as substrate, arylamine acetyltransferase activity in pigeon liver was about 8 times greater than in chicken liver, and about 40 times greater than in rabbit.