Kinetics of acetyl CoA: Arylamine N‐Acetyltransferase in rapid and slow acetylator livers from the Pelecypoda Cristaria plicata

N‐acetyltransferase (NAT) activity was determined in the livers of 50 freshwater mussels (Cristaria plicata), using 2‐aminofluorene (AF) and p‐aminobenzoic acid (PABA) as substrates. The activities (means ± s.d.) of NAT in freshwater mussel livers were 1.29 ± 0.12, 0.79 ±0.08, and 0.41 ± 0.06 nmol/min/mg protein for the acetylation of AF and 1.12 ± 0.10, 0.71 ± 0.09, and 0.32 ± 0.04 nmol/min/mg protein for the acetylation of PABA. An apparent Km difference for AF and PABA in the freshwater mussel livers were found to be of high and low acetylator activity. Based on the AF‐NAT activity of the livers, there appears to be a polymorphism in NAT activity with 22 rapid, 12 intermediate, and 16 slow acetylators among the 50 freshwater mussels livers were assayed. This report is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in a pelecypoda and could lead to the development of a freshwater mussels model for monitoring the effects of pollution in freshwater environments on natural sp...