title: Aspirin hydrolyzing esterases from rat liver cytosol.
abstract: Unlike most esterases, which are predominantly bound to the microsomal fraction, the enzymes hydrolyzing acetylsalicylic acid are present in an equal amount in the cytosol. Two soluble isozymes were purified to homogeneity from rat liver and characterized as serine esterases with a Mr of 35,000. Both had the wide substrate spectrum characteristic of enzymes active in detoxication. Both had a very low Km for acetylsalicylate. Three other cytoplasmic enzymes active with aspirin were observed but these differed in their high Mr (about 220,000) and their lack of reactivity with antibody to one of the homogeneous isozymes.
authors.affiliation: Laboratory of Biochemistry and Metabolism, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: D H
authors.initials: DH
authors.lastname: Kim
authors.forename: Y S
authors.initials: YS
authors.lastname: Yang
authors.forename: W B
authors.initials: WB
authors.lastname: Jakoby
mesh_terms: D000818:Animals; D001241:Aspirin / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D003600:Cytosol / Q000201:enzymology; D004950:Esterases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D009596:Nitrophenols / Q000494:pharmacology; D010261:Paraoxon / Q000494:pharmacology; D051381:Rats; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D009596:Nitrophenols; C002887:bis(4-nitrophenyl)phosphate; D004950:Esterases; C022635:serine esterase; D010261:Paraoxon; D001241:Aspirin