Interaction between D-glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase and its functional...

E. coli D-glyceraldehyde-3-phosphate dehydrogenase covalently bound to Sepharose was shown to form a complex with soluble E. coli 3-phosphoglycerate kinase with a stoichiometry of 1.77 +/- 0.61 kinase molecules per tetramer of the dehydrogenase and an apparent Kd of 1.03 +/- 0.68 microM (10 mM sodium phosphate, 0.15 M NaCl). No interaction was detected between E. coli D-glyceraldehyde-3-phosphate dehydrogenase and rabbit muscle 3-phosphoglycerate kinase. The species-specificity of the bienzyme association made it possible to develop a kinetic approach to demonstrate the functionally significant interaction between E. coli D-glyceraldehyde-3-phosphate dehydrogenase and E. coli 3-phosphoglycerate kinase, which consists of an increase in steady-state rate of the coupled reaction.