Kinetics of acetyl coenzyme A:: Arylamine N-acetyltransferase from human cumulus cells

Purpose: N-acetyltransferase (NAT) activity is involved in the detoxification of exogenous amines. We aimed to evaluate the kinetics of acetyl coenzyme A (AcCoA): arylamine NAT for human cumulus cells. Methods. Thirty in fertile women who were undergoing controlled ovarian hyperstimulation (COH) and oocyte retrievals were recruited Human cumulus cells were obtained during oocyte retrievals. Using 2-aminofluorene (2-AF) and p-aminobenzoicacid (PABA) as substrates, NAT activity and Michaelis-Menten kinetics constants of all samples were determined by using high-pressure liquid chromatography. Results. There were 6 rapid, 10 intermediate, and 14 slow acetylators. 2-AF-NAT and PABA-NAT activities were 0.97 +/- 0.74 and 0.89 +/- 0.77 nmol/min/mg protein, respectively. Km/V-max of rapid and slow acetylators for 2-AF were (161 +/- 55)/(15.6 +/- 2.9) and (27.8 +/- 11.4)/(2.6 +/- 0.9), respectively. Km/V-max of rapid and slow acetylators for PABA were (104 +/- 36)/(13.2 +/- 2.8) versus (20.0 +/- 10)/(2.0 +/- 0.7), respectively Compared to slow acetylators, the rapid acetylators exhibited higher Km/V-max values for 2-A F (5.8-/6-fold) and PABA (6-/6.6-fold), respectively. Conclusion. Human cumulus could acetylate arylamine carcinogen (2-AF) and noncarcinogen drug (PABA). Higher percentage of rapid acetylators established in the cumulus during COH. It provides a model for monitoring the effects of pollution or carcinogenesis upon the oocyte during COH and oocyte retrievals.