Evidence for two closely related isozymes of arylamine N-acetyltransferase in human liver.
Acetyl CoA-dependent arylamine N-acetyltransferase (EC 2.3.1.5) is the target of a genetic polymorphism in the metabolism of drugs and carcinogens. N-Acetyltransferase was purified 1000-fold from cytosol of human liver and its identity was verified by amino acid sequence homology of two of its tryptic peptides with published rabbit and chicken N-acetyltransferase sequences. Enzyme activity correlated with the presence of two proteins, NAT-1 and NAT-2, with indistinguishable molecular masses (31 kDa). NAT-1 and NAT-2 could be separated by anion-exchange chromatography and were functionally distinguished by their different apparent affinities for the acceptor amine sulfamethazine (SMZ). Antibodies raised against NAT-1 were able to recognize both isozymes on Western blots.
Grant
D M
DM
Department of Pharmacology, University of Basel, Switzerland.
Lottspeich
F
F
Meyer
U A
UA
D000123:Acetyltransferases / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D015153:Blotting, Western; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments; D011110:Polymorphism, Genetic; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity; D013418:Sulfamethazine / Q000378:metabolism; D014357:Trypsin
D007527:Isoenzymes; D010446:Peptide Fragments; D013418:Sulfamethazine; D000123:Acetyltransferases; D001191:Arylamine N-Acetyltransferase; D014357:Trypsin