Influence of Phosphoenolpyruvate on the Dynamic Behaviour of Phosphofructokinase ofEscherichia coli

The effect of phosphoenolpyruvate (PEP) and the substrate input rate (σ1) on the dynamic behaviour of the phosphofructokinase (EC 2.7.1.11) (PFK) ofEscherichia coliis analysed. The mathematical model is based on a well defined one and all kinetic parameters used in this analysis correspond specifically to the PFK of E. coli. Results agree with previous reports only when the concentration of PEP is very low (< 10 μM) but change at higher concentrations. The analysis of the local stability of PFK reveals the existence of nodes, spirals of limit cycles whose dynamic maps depended on the concentration of PEP and the substrate input rate. Phosphofructokinase shows higher sensitivity at concentrations of PEP close to those expected inE. coli(0.1–0.5 mM). The effect of PEP on the stability of PFK is complex and depends on the range of PEP concentration range of PEP concentration and σ1. For a given value of PEP (e.g. 1 mM), PFK can change or even reverse the stability pattern when σ1, changes within a particular range of values of this variable.