On the role of enzyme cooperativity in metabolic oscillations: analysis of the Hill coefficient in a model for glycolytic periodicities.
The role of enzyme cooperativity in the mechanism of metabolic oscillations is analyzed in a concerted allosteric model for the phosphofructokinase reaction. This model of a dimer enzyme activated by the reaction product accounts quantitatively for glycolytic periodicities observed in yeast and muscle. The Hill coefficient characteristic of enzyme-substrate interactions is determined in the model, both at the steady state and in the course of sustained oscillations. Positive cooperativity is a prerequisite for periodic behavior. A necessary condition for oscillation  in a dimer K system is a Hill coefficient larger than 1.6 at the unstable stationary state. The analysis suggests that positive as well as negative effectors of phosphofructokinase inhibit glycolytic oscillations by inducing a decrease in enzyme cooperativity. The results are discussed with respect to glycolytic and other metabolic periodicities.
D000494:Allosteric Regulation; D000818:Animals; D006019:Glycolysis; D007700:Kinetics; D008433:Mathematics; D009132:Muscles / Q000201:enzymology; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013045:Species Specificity
D010732:Phosphofructokinase-1