title: The reactions of 1,10-phenanthroline with yeast alcohol dehydrogenase.
abstract: Freshly prepared samples of yeast alcohol dehydrogenase (EC 1.1.1.1) were inhibited by 1,10-phenanthroline at pH 7.0 and 0 degrees C in a two-stage process. The first step appeared to be slowly established, but was rendered reversible by removal of reagent or by addition of excess Zn2+ ions. The second step was irreversible and was associated with the dissociation of the tetrameric enzyme. The presence of saturating concentrations of NAD+ or NADH promoted and enhanced inhibition by the slowly established reversible process, but prevented dissociation of the enzyme. For the incubation mixtures containing NAD+, removal of the 1,10-phenanthroline resulted in virtually complete recovery of activity, whereas, for the incubation mixtures containing NADH, removal of the reagent gave only partial re-activation. The presence of NAD+ and pyrazole, or NADH and acetamide, in incubation mixtures with the enzyme gave rise to ternary complexes that gave protection against both forms of inactivation by 1,10-phenanthroline. The results support the view that at least some of the Zn2+ ions associated with yeast alcohol dehydrogenase have a catalytic, as opposed to a purely structural, role.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007700:Kinetics; D009243:NAD; D010618:Phenanthrolines / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D015032:Zinc / Q000378:metabolism
chemical_list: D010618:Phenanthrolines; D009243:NAD; D000429:Alcohol Oxidoreductases; D015032:Zinc