Effect of NADH-X on cytosolic glycerol-3-phosphate dehydrogenase

Arch Biochem Biophys. 1998 Dec 15;360(2):195-205. doi: 10.1006/abbi.1998.0939.


At pH 7.05 NADH-X prepared by incubating NADH with glyceraldehyde-3-phosphate dehydrogenase (E.C. was a potent noncompetitive inhibitor, with respect to coenzyme, of NADPH oxidation by pure rabbit muscle cytosolic glycerol-3-phosphate dehydrogenase (E.C. and also a potent inhibitor of NADPH oxidation catalyzed by this enzyme in a rat pancreatic islet cytosolic fraction. It was a much less potent inhibitor of NADPH oxidation catalyzed by this enzyme in a rat liver cytosolic fraction and of NADH oxidation catalyzed by this enzyme from all three sources. Glycerol-3-phosphate dehydrogenase purified from muscle cytosol contains tightly bound NADH-X, NAD, and ADP-ribose, each in amounts of about 0.1 mol per mole of enzyme polypeptide chain. A deproteinized supernatant of this enzyme contained these three ligands and produced the same type of inhibition of the enzyme described above for prepared NADH-X with a Ki, in the reaction with NADPH at pH 7.05, in the range of 0.2 microM with respect to the total concentration of ligands ([ADP-ribose] + [NAD] + [NADH-X] = 0. 2 microM). However, only the NADH-X component could account for the potent inhibition because NAD, ADP-ribose, and the primary acid product (which can be produced from NADH-X) each had a Ki considerably higher than 0.2 microM. Although at pH 7.05 NADH-X inhibited NADPH oxidation considerably more than NADH oxidation, the reverse was the case at pH 7.38. Since the enzyme purified from muscle contains tightly bound NADH-X, NADH-X might become attached to the enzyme in vivo where it could play a role in regulating the ratio of NADH to NADPH oxidation of the enzyme.

Publication types

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

MeSH terms

  • Adenosine Diphosphate Ribose / metabolism
  • Animals
  • Chromatography, High Pressure Liquid
  • Cytosol / enzymology
  • Dialysis
  • Enzyme Activation
  • Glyceraldehyde-3-Phosphate Dehydrogenases / metabolism
  • Glycerol-3-Phosphate Dehydrogenase (NAD+)
  • Glycerolphosphate Dehydrogenase / antagonists & inhibitors
  • Glycerolphosphate Dehydrogenase / metabolism*
  • Hydrogen-Ion Concentration
  • Islets of Langerhans / enzymology
  • Kinetics
  • Ligands
  • Liver / enzymology
  • Muscle, Skeletal / enzymology
  • NAD / metabolism*
  • NAD / pharmacology
  • NADP / metabolism*
  • Oxidation-Reduction
  • Rabbits
  • Rats


  • Ligands
  • NAD
  • Adenosine Diphosphate Ribose
  • NADP
  • Glycerolphosphate Dehydrogenase
  • Glycerol-3-Phosphate Dehydrogenase (NAD+)
  • Glyceraldehyde-3-Phosphate Dehydrogenases