A simple approach to detect active-site-directed enzyme-enzyme interactions. The aldolase/glycerol-phosphate-dehydrogenase enzyme system. 1987

B Vértessy, and J Ovádi

A novel approach has been elaborated to identify the mechanism of intermediate transfer in interacting enzyme systems. The aldolase/glycerol-3-phosphate-dehydrogenase enzyme system was investigated since complex formation between these two enzymes had been demonstrated. The kinetics of dihydroxyacetone phosphate conversion catalyzed by the dehydrogenase in the absence and presence of aldolase was analyzed. It was found that the second-order rate constant (kcat/Km) of the enzymatic reaction decreases due to the formation of a heterologous complex. The decrease could be attributed to an increase of the Km value since kcat did not change in the presence of aldolase. In contrast, an apparent increase in the second-order rate constant of dihydroxyacetone phosphate conversion by the dehydrogenase was observed if the triose phosphate was produced by aldolase from fructose 1,6-bisphosphate (consecutive reaction). Moreover, no effect of dihydroxyacetone phosphate on the dissociation constant of the heterologous enzyme complex could be detected by physico-chemical methods. The results suggest that the endogenous dihydroxyacetone phosphate produced by aldolase complexed with dehydrogenase is more accessible for the dehydrogenase than the exogenous one, the binding of which is impeded due to steric hindrance by bound aldolase.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D009097 Multienzyme Complexes Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES. Complexes, Multienzyme
D002384 Catalysis The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction. Catalyses
D004099 Dihydroxyacetone Phosphate An important intermediate in lipid biosynthesis and in glycolysis. Dihydroxyacetone 3-Phosphate,3-Phosphate, Dihydroxyacetone,Dihydroxyacetone 3 Phosphate,Phosphate, Dihydroxyacetone
D005634 Fructose-Bisphosphate Aldolase An enzyme of the lyase class that catalyzes the cleavage of fructose 1,6-biphosphate to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. The enzyme also acts on (3S,4R)-ketose 1-phosphates. The yeast and bacterial enzymes are zinc proteins. (Enzyme Nomenclature, 1992) E.C. 4.1.2.13. Aldolase,Fructosediphosphate Aldolase,Aldolase A,Aldolase B,Aldolase C,Fructose 1,6-Bisphosphate Aldolase,Fructose 1,6-Bisphosphate Aldolase, Class II,Fructose 1-Phosphate Aldolase,Fructose Biphosphate Aldolase,Fructosemonophosphate Aldolase,1,6-Bisphosphate Aldolase, Fructose,Aldolase, Fructose 1,6-Bisphosphate,Aldolase, Fructose 1-Phosphate,Aldolase, Fructose Biphosphate,Aldolase, Fructose-Bisphosphate,Aldolase, Fructosediphosphate,Aldolase, Fructosemonophosphate,Fructose 1 Phosphate Aldolase,Fructose 1,6 Bisphosphate Aldolase,Fructose Bisphosphate Aldolase
D005993 Glycerolphosphate Dehydrogenase Alpha-Glycerophosphate Dehydrogenase,Glycerol-3-Phosphate Dehydrogenase,Glycerophosphate Dehydrogenase,Glycerophosphate Oxidase,Alpha Glycerophosphate Dehydrogenase,Dehydrogenase, Alpha-Glycerophosphate,Dehydrogenase, Glycerol-3-Phosphate,Dehydrogenase, Glycerolphosphate,Dehydrogenase, Glycerophosphate,Glycerol 3 Phosphate Dehydrogenase,Oxidase, Glycerophosphate
D001665 Binding Sites The parts of a macromolecule that directly participate in its specific combination with another molecule. Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667 Binding, Competitive The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements. Competitive Binding

Related Publications

B Vértessy, and J Ovádi
December 1982, Archives of biochemistry and biophysics,
B Vértessy, and J Ovádi
February 1976, The Biochemical journal,
Copied contents to your clipboard!