Physical and enzymatic properties of a class II alcohol dehydrogenase isozyme of human liver: pi-ADH

Biochemistry. 1984 Dec 18;23(26):6363-8. doi: 10.1021/bi00321a012.


Homogeneous class II alcohol dehydrogenase (pi-ADH) has been isolated from human liver homogenates by chromatography on DE-52 cellulose, 4-[3-[N-(6-amino-caproyl)amino]propyl]pyrazole-Sepharose, SP-Sephadex C-50, and agarose-hexane-AMP, yielding an enzyme that has a significantly higher specific activity and is markedly more stable than that isolated by an earlier procedure. pi-ADH is composed of two identical 40 000-dalton subunits, contains 4 mol of zinc/dimer, and is readily inhibited by metal-chelating agents. The purified enzyme binds two molecules of coenzyme per dimer, exhibits an absorption maximum at 280 nm, epsilon 280 = 57 000, and exhibits an isoelectric point of 8.6. The class II isozyme catalyzes the oxidation of a variety of alcohols with Km values ranging from 7 microM to 560 mM and with kcat values from 32 min-1 to 600 min-1 and demonstrates a preference for hydrophobic substrates. The kcat/Km ratio for ethanol oxidation exhibits a pH maximum at 10.4.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alcohol Dehydrogenase
  • Alcohol Oxidoreductases / antagonists & inhibitors
  • Alcohol Oxidoreductases / isolation & purification
  • Alcohol Oxidoreductases / metabolism*
  • Chelating Agents / pharmacology
  • Humans
  • In Vitro Techniques
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / isolation & purification
  • Isoenzymes / metabolism*
  • Kinetics
  • Liver / enzymology*
  • Substrate Specificity


  • Chelating Agents
  • Isoenzymes
  • Alcohol Oxidoreductases
  • Alcohol Dehydrogenase