Kinetics of arylamine N-acetyltransferase in tissues from rapid and slow acetylator mice.
Kinetic parameters for arylamine N-acetyltransferase activity in liver, blood, and bladder from C57BL/6J and A/J mouse strains were determined using an improved assay system, and some deviations were found from previously reported results. In the present studies, blood N-acetyltransferase activity with p-aminobenzoic acid and 2-aminofluorene as substrates was 20- and 10-fold greater, respectively, in C57BL/6J than in A/J mice. Urinary bladder possessed N-acetyltransferase activity for both 2-aminofluorene and p-aminobenzoic acid which differed 2-fold, and reflected the liver and blood phenotype. An apparent Km difference for 2-aminofluorene was observed between C57BL/6J and A/J liver N-acetyltransferase. Contrary to earlier studies, the liver N-acetyltransferase activity differed 3-fold between the A/J and C57BL/6J mouse strains, with either p-aminobenzoic acid or 2-aminofluorene as substrates. Dimethylsulfoxide at concentrations used in the 2-aminofluorene acetylation assay in earlier studies, inhibited the A/J liver N-acetyltransferase to a greater extent than the C57BL/6J enzyme, which may have contributed to the larger difference in liver NAT activity with 2-aminofluorene reported previously.
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism*; D003124:Colorimetry; D005449:Fluorenes / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D051379:Mice; D008805:Mice, Inbred A / Q000378:metabolism*; D008810:Mice, Inbred C57BL / Q000378:metabolism*; D010641:Phenotype; D001743:Urinary Bladder / Q000201:enzymology
D005449:Fluorenes; D007527:Isoenzymes; C012177:2-aminofluorene; D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase