4-Hydroxy-2-Nonenal Hardly Affects Glycolysis

4-Hydroxy-2-nonenal (HNE), one of the major products of lipid peroxidation, inactivated the rate-limiting enzymes (from animal sources) of the glycolytic pathway and the pentose phosphate pathway when incubated at 37°C for 1 h in the absence of glutathione (GSH). The HNE concentration for half-maximal inactivation of 6-phosphofructokinase (PFK) and glyceraldehyde-3-phosphate dehydrogenase was 3–10 μM; and that value for pyruvate kinase, glucose-6-phosphate dehydrogenase, and hexokinases I and II was 0.15-0.6 mM. In the presence of 5 mM GSH, however, only PFK, irrespective of the source (muscle, liver, or erythrocyte), was inactivated by 40–-50% when incubated with 0.1 mM HNE for 1 h. Even PFK was not inactivated in the presence of both GSH and its substrate, ATP (2 mM). Glycolysis in human erythrocytes was not affected by treatment of cells with 0.1 mM HNE at 37°C for 30 min. The results suggest that HNE, at concentrations observable under physiological and pathological conditions, hardly affects glycolysis in cells.