Substrate-induced dissociation of glycerol-3-phosphate dehydrogenase and its complex formation with fructose-bisphosphate aldolase.
A threefold decrease in specific activity of glycerol-3-phosphate dehydrogenase was found on going from 800 nM to 10 nM enzyme concentration. According to ultracentrifugal analyses the dimeric glycerol-3-phosphate dehydrogenase (molecular weight 78,000) dissociates into monomers in the equilibrium mixture of its substrates and products. The concentration-dependent decrease in the specific activity is interpreted as a consequence of subunit dissociation and the estimated dissociation constants are 0.7 micro M and 3.5 micro M at 38 degrees C and 20 degrees C respectively. According to active-enzyme-band centrifugation experiments and kinetic analysis aldolase forms a complex with glycerol-3-phosphate dehydrogenase and this complex formation influences the specific activity of the dehydrogenase. The interaction between glycerol-3-phosphate dehydrogenase and aldolase can provide a regulatory mechanism at the branching point of glycolytic and lipid metabolic pathways.
D000818:Animals; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism*; D007700:Kinetics; D011817:Rabbits; D013379:Substrate Specificity; D014461:Ultracentrifugation
D005993:Glycerolphosphate Dehydrogenase; D005634:Fructose-Bisphosphate Aldolase