title: Rat liver polysome N alpha-acetyltransferase: isolation and characterization.
abstract: Rat liver polysome N alpha-acetyltransferase has been purified to homogeneity by a four-step procedure that utilizes ammonium sulfate precipitation, gel filtration, hydroxylapatite chromatography, and Mono Q ion exchange chromatography. The enzyme is greatly stabilized by the inclusion of EDTA and 0.01% deoxycholate in the isolation buffers. The purified enzyme has a native molecular weight of 190,000 and a subunit molecular weight of 95,000, suggesting that it is a homodimer. The enzyme shows a pH optimum of 8.0 and is strongly inhibited by Cl-, I-, SCN-, and ClO4- and to a lesser degree by sulfate and acetate. It is unaffected by phosphate, citrate, and F- and by Na+ and K+; NH4+ is partially inhibitory. The enzyme is also sensitive to iodoacetic acid. It is generally more similar to yeast N alpha-acetyltransferase [Lee, F.-J. S., Lin, L.-W., & Smith, J. A. (1988) J. Biol. Chem. 263, 14948-14955] than to the hen oviduct enzyme, which contains a 7S RNA subunit [Kamitani, K., & Sakiyama, F. (1989) J. Biol. Chem. 264, 13194-13198], although the amino acid compositions are quite different.
authors.affiliation: Department of Biological Chemistry, College of Medicine, University of California, Irvine 92717.
authors.forename: R
authors.initials: R
authors.lastname: Yamada
authors.forename: R A
authors.initials: RA
authors.lastname: Bradshaw
mesh_terms: D000123:Acetyltransferases / Q000737:chemistry / Q000302:isolation & purification*; D000596:Amino Acids / Q000032:analysis; D000645:Ammonium Sulfate; D000818:Animals; D002845:Chromatography; D002951:Citrates / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D008099:Liver / Q000201:enzymology; D008297:Male; D008970:Molecular Weight; D063206:N-Terminal Acetyltransferases; D011132:Polyribosomes / Q000201:enzymology*; D011189:Potassium Chloride / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012680:Sensitivity and Specificity; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D000596:Amino Acids; D002951:Citrates; D007461:Iodoacetates; D011480:Protease Inhibitors; D011189:Potassium Chloride; D000123:Acetyltransferases; D063206:N-Terminal Acetyltransferases; D000645:Ammonium Sulfate; D019807:Iodoacetic Acid