title: Some properties of an alcohol dehydrogenase partially purified from baker's yeast grown without added zinc.
abstract: Alcohol dehydrogenase was partially purified from yeast (Saccharomyces cerevisiae) grown in the presence of 20 muM-MnSO4 without added Zn2+ and from yeast grown in the presence of 1.8 muM-MnSO4. The enzyme from yeast grown with added Zn2+ has the same properties as the crystalline enzyme from commercial supplies of baker's yeast. The enzyme from yeast grown without added An2+ has quite different properties. It has a mol.wt. in the region of 72000 and an S 20 w of 5.8S. The values can be compared with a mol.wt. of 141000 and an S 20 w of 7.6S for the crystalline enzyme. ADP-ribose, a common impurity in commercial samples of NAD+, is a potent competitive inhibitor of the new enzyme (K1 = 0.5 muM), but is not so for the crystalline enzyme. The observed maximum rate of ethanol oxidation at pH 7.05 and 25 degrees C was decreased 12-fold by the presence of 0.06 mol of inhibitor/mol of NAD+ when using the enzyme from Zn2+-deficient yeast, but with crystalline enzyme the maximum rate was essentially unchanged by this concentration of inhibitor. The kinetic characteristics for the two enzymes with ethanol, butan-1-ol, acetaldehyde and butyraldehyde as substrates are markedly different. These kinetic differences are discussed in relation to the mechanism of catalysis for the enzyme from Zn2+-deficient yeast.
mesh_terms: D000079:Acetaldehyde; D000247:Adenosine Diphosphate Sugars / Q000494:pharmacology; D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D000447:Aldehydes; D000440:Butanols; D000431:Ethanol; D007700:Kinetics; D008345:Manganese / Q000032:analysis; D008970:Molecular Weight; D009243:NAD; D012441:Saccharomyces cerevisiae / Q000032:analysis / Q000201:enzymology*; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
chemical_list: D000247:Adenosine Diphosphate Sugars; D000447:Aldehydes; D000440:Butanols; D009243:NAD; D000431:Ethanol; D008345:Manganese; D000429:Alcohol Oxidoreductases; D000079:Acetaldehyde; D015032:Zinc