Identification of arylamine N-acetyltransferase activity in the bovine lens.

Arylamine N-acetyltransferase (NAT) activity was identified and partially characterized in the bovine lens. According to size-exclusion HPLC, the molecular mass of the arylamine NAT is approximately 30-kDa. Based upon substrate specificity analysis, it is best described as an arylamine NAT which has some ability to N-acetylate arylalkylamines. This arylamine NAT acetylates para-aminobenzoic acid thereby demonstrating a monomorphic pattern of N-acetylation. It demonstrates low sensitivity to methotrexate inhibition as indicated by the relatively high IC50 value (470 microM). NAT could be involved in lenticular detoxification of both endogenous amines and exogenous drugs.