title: Identification of a botulinum C3-like enzyme in bovine brain that catalyzes ADP-ribosylation of GTP-binding proteins.
abstract: A novel enzyme activity was found in bovine brain cytosol that transfers the ADP-ribosyl moiety of NAD to proteins with Mr values of 22,000 and 25,000. The substrates were the same GTP-binding proteins serving as the substrate of an ADP-ribosyltransferase C3 which was produced by a type C strain of Clostridium botulinum. The brain enzyme was partially purified from the cytosol and had a molecular mass of approximately 20,000 on a gel filtration column. The brain endogenous enzyme displayed unique properties similar to those observed with botulinum C3 enzyme. The enzyme activity was markedly stimulated by a protein factor that had been initially found in the cytosol as an activator for botulinum C3-catalyzed ADP-ribosylation (Ohtsuka, T., Nagata, K., Iiri, T., Nozawa, Y., Ueno, K., Ui, M., and Katada, T. (1989) J. Biol. Chem. 264, 15000-15005). The activity of the brain enzyme was also affected by certain types of detergents or phospholipids. The substrate of the brain enzyme was specific for GTP-binding proteins serving as the substrate of botulinum C3 enzyme; the alpha-subunits of trimeric GTP-binding proteins which served as the substrate of cholera or pertussis toxin were not ADP-ribosylated by the endogenous enzyme. Thus, this is the first report showing an endogenous enzyme in mammalian cells that catalyzes ADP-ribosylation of small molecular weight GTP-binding proteins.
authors.affiliation: Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Maehama
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Ohoka
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: M
authors.initials: M
authors.lastname: Ui
authors.forename: T
authors.initials: T
authors.lastname: Katada
mesh_terms: D036002:ADP Ribose Transferases / Q000737:chemistry*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D001905:Botulinum Toxins; D001921:Brain / Q000201:enzymology*; D002384:Catalysis; D002417:Cattle; D002850:Chromatography, Gel; D002373:Cyclic AMP Receptor Protein / Q000494:pharmacology; D003840:Deoxycholic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000378:metabolism*; D010743:Phospholipids / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D013379:Substrate Specificity; D014357:Trypsin
chemical_list: D002373:Cyclic AMP Receptor Protein; D010743:Phospholipids; D003840:Deoxycholic Acid; D000246:Adenosine Diphosphate Ribose; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D011065:Poly(ADP-ribose) Polymerases; D014357:Trypsin; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins