Kinetics of acetyl coenzyme A: arylamine N-acetyltransferase from human cumulus cells.
OBJECTIVE
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 infertile 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-aminobenzoic acid (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/Vmax 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/Vmax 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/Vmax values for 2-AF (5.8-/6-fold) and PABA (6-/6.6-fold), respectively.


CONCLUSIONS
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.
Chang
C C
CC
Department of Obstetrics and Gynecology, China Medical College Hospital, No. 2 Yuh-Der Road, Taichung, Taiwan.
Hsieh
Y Y
YY
Chung
J G
JG
Tsai
H D
HD
Tsai
C H
CH
D010129:4-Aminobenzoic Acid / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism*; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D005449:Fluorenes / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism*; D010053:Ovary / Q000166:cytology
D005449:Fluorenes; C012177:2-aminofluorene; D000105:Acetyl Coenzyme A; D001191:Arylamine N-Acetyltransferase; D010129:4-Aminobenzoic Acid