title: Selective inhibition of Zn(2+)-glycerophosphocholine cholinephosphodiesterase by tellurium tetrachloride.
abstract: A Zn(2+)-glycerophosphocholine cholinephosphodiesterase (EC 3.1.4.38) purified from mouse brain was found to be reversibly inhibited by tellurium tetrachloride. This effect was characterized by a competitive pattern of inhibition, with apparent Ki values of 0.7 microM and 1.5 microM for the hydrolysis of p-nitrophenylphosphocholine and glycerophosphocholine respectively. Interestingly, the inhibitory effect of tellurium tetrachloride was found to be greatly potentiated by tetramethylammonium salt, indicative of a synergistic interaction between the two compounds. Additionally, it was observed that the effect of tellurium tetrachloride was not affected by a number of other metal ions, and was more pronounced at neutral pH, suggesting that the inhibitory role of the tellurium tetrachloride may be of importance under physiological conditions. Thus Zn(2+)-glycerophosphocholine cholinephosphodiesterase is proposed to be one of the target enzymes which is susceptible to the inhibitory effect of tellurium tetrachloride.
authors.affiliation: Daejeon Machine Depot, Korea.
authors.forename: D E
authors.initials: DE
authors.lastname: Sok
authors.forename: M R
authors.initials: MR
authors.lastname: Kim
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002413:Cations, Divalent / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004492:Edetic Acid / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012643:Selenium / Q000494:pharmacology; D013691:Tellurium / Q000494:pharmacology*; D015032:Zinc / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D010726:Phosphodiesterase Inhibitors; D000644:Quaternary Ammonium Compounds; D004492:Edetic Acid; C036605:tellurium tetrachloride; D010727:Phosphoric Diester Hydrolases; C061931:glycerophosphocholine cholinephosphodiesterase; C027917:tetramethylammonium; D012643:Selenium; D015032:Zinc; D013691:Tellurium