The human beta 3 alcohol dehydrogenase subunit differs from beta 1 by a Cys for Arg-369 substitution which decreases NAD(H) binding

Biochem Biophys Res Commun. 1987 Aug 14;146(3):1127-33. doi: 10.1016/0006-291x(87)90779-0.

Abstract

The beta 3 beta 3 (formerly called beta Indianapolis) and beta 1 beta 1 isoenzymes of human alcohol dehydrogenase differ substantially in their catalytic properties. Specifically, the KM value for NAD+ of beta 3 beta 3 is 70 times greater than that of beta 1 beta 1, and the Ki value for NADH is 35 times greater than that of beta 1 beta 1. To identify the structural basis of these catalytic differences, we sequenced regions of the beta 3 subunit and the beta 3 gene. beta 3 differs from beta 1 by the substitution of Cys for Arg-369. Based on x-ray crystallography of horse ADH, Arg-369 should interact with the nicotinamide phosphate moiety of NAD(H). The Cys for Arg-369 substitution would decrease the enzyme's affinity for coenzyme and, thus, account for the observed kinetic differences between beta 3 beta 3 and beta 1 beta 1.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alcohol Dehydrogenase / genetics*
  • Alcohol Dehydrogenase / metabolism
  • Amino Acid Sequence
  • Arginine*
  • Binding Sites
  • Cysteine*
  • Humans
  • Isoenzymes / genetics*
  • Isoenzymes / metabolism
  • Liver / enzymology*
  • Macromolecular Substances
  • NAD / metabolism*
  • Oxidation-Reduction
  • Peptide Fragments / analysis
  • Protein Binding

Substances

  • Isoenzymes
  • Macromolecular Substances
  • Peptide Fragments
  • NAD
  • Arginine
  • Alcohol Dehydrogenase
  • Cysteine