The cellular distribution of free and bound glycolytic enzymes in vivowas estimated by means of a model based on previously determined association constants for individual binding interactions and in vivoprotein concentrations. The calculations revealed that a significant proportion of the enzymes would be either associated with F-actin, or bound in binary enzyme-enzyme complexes in vivo. An analysis of the relative concentration, and relative activity, of F-actin-bound enzymes suggested that a complete glycolytic complex, composed of all enzymatic steps from phosphofructokinase (PFK) to lactate dehydrogenase (LDH) does not exist. This was indicated by a very low concentration of F-actin-associated phosphoglycerate kinase (PGK) and by a very low activity of F-actin bound aldolase and PGK; this model showed that aldolase and PGK would be absent from any F-actin bound complex. An analysis of soluble enzyme-enzyme associations indicated that formation of binary enzyme complexes may lead to an increased overall flux through glyceraldehyde 3-phosphate dehydrogenase and LDH, but would serve to decrease flux through PFK and aldolase. A 1·4-fold activation of PFK, which occurs when the soluble enzyme binds to F-actin, suggested that reversible binding of PFK to F-actin may represent a novel cellular mechanism for controlling glycolytic flux during periods of increased metabolic demand by controlling the key regulatory enzyme of glycolysis.

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Journal Journal of Theoretical Biology
Brooks, S.P.J. (Stephen P.J.), & Storey, K. (1991). A quantitative evaluation of the effect of enzyme complexes on the glycolytic rate in vivo: Mathematical modeling of the glycolytic complex. Journal of Theoretical Biology, 149(3), 361–375. doi:10.1016/S0022-5193(05)80311-X