Kinetics of acetyl coenzyme A: arylamine N-acetyltransferase from rapid and slow acetylator human benign prostatic hyperplasia tissues.

Abstract

N-acetyltransferase (NAT) activity was determined in 40 human benign prostatic hyperplasia tissues using 2-aminofluorene (AF) and p-aminobenzoic acid (PABA) as substrates. These were then assayed by high performance liquid chromatography for determining the amounts of acetylated AF and PABA and non-acetylated AF and PABA. The activities (mean +/- SD) of AF-NAT from human benign prostatic hyperplasia tissues were divided into rapid (2.06 +/- 0.08 nmol/min per milligram protein), intermediate (1.25 +/- 0.26 nmol/min per milligram protein), and slow (0.58 +/- 0.30 nmol/min per milligram protein) acetylator groups. The activities (mean +/- SD) of PABA-NAT from human benign prostatic hyperplasia tissues were also divided into rapid (2.00 +/- 0.00 nmol/min per milligram protein), intermediate (1.25 +/- 0.18 nmol/min per milligram protein), and slow (0.48 +/- 0.29 nmol/min per milligram protein) acetylator groups. Kinetic constants for arylamine NAT activities were determined for each of these acetylator groups. Apparent differences in Km and Vmax for AF were found. Therefore, there seems to be a polymorphism in NAT activity with two rapid, five intermediate, and 33 slow acetylators among the 40 samples assayed. This is the first demonstration of acetyl CoA-arylamine NAT activity in human benign prostatic hyperplasia tissues.