4-hydroxynonenal inhibits Na(+)-K(+)-ATPase

Free Radic Biol Med. 1996;20(2):215-23. doi: 10.1016/0891-5849(95)02041-1.

Abstract

4-Hydroxynonenal binds rapidly to Na(+)-K(+)-ATPase, and this was accompanied by a decrease in measurable sulfhydryl groups and a loss of enzyme activity. The I50 value for Na(+)-K(+)-ATPase inhibition by 4-hydroxynonenal was found to be 120 microM. Although the sulfhydryl groups could be completely restored with beta-mercaptoethanol during the reaction of the Na(+)-K(+)-ATPase-HNE-adduct, the Na(+)-K(+)-ATPase activity was only partially restored by this reducing agent. A combination of hydroxylamine and beta-mercaptoethanol yielded the greatest recovery of enzyme activity, 85% of original. Thus, 4-hydroxynonenal binding to Na(+)-K(+)-ATPase led to an irreversible decrease of enzyme activity under the conditions employed. It is hypothesized that 4-hydroxynonenal reacts with sulfhydryls at sites on the enzyme that are inaccessible by beta-mercaptoethanol. Furthermore, evidence was obtained that 4-hydroxynonenal reacts with other amino acids such as lysine to form adducts that also interfere with protein function.

Publication types

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

MeSH terms

  • Aldehydes / pharmacology*
  • Cell Membrane / enzymology
  • Cross-Linking Reagents
  • Enzyme Inhibitors / pharmacology*
  • Kinetics
  • Mercaptoethanol / pharmacology
  • Ouabain / pharmacology
  • Oxidation-Reduction
  • Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors*
  • Sulfhydryl Compounds

Substances

  • Aldehydes
  • Cross-Linking Reagents
  • Enzyme Inhibitors
  • Sulfhydryl Compounds
  • Ouabain
  • Mercaptoethanol
  • Sodium-Potassium-Exchanging ATPase
  • 4-hydroxy-2-nonenal