EI of the Phosphotransferase System ofEscherichia coli: Mathematical Modeling Approach to Analysis of Its Kinetic Properties

Abstract

The mathematical model of the operation of the first enzyme of theEscherichia coliphosphotransferase system, EI, is proposed. Parameters of the kinetic model describing the operation of EI under different conditions are identified on the basis of a large amount of known experimental data. The verified model is employed to predict modes of operation of EI under bothin vivophysiological conditions andin vitrononphysiological conditions. The model predicts that underin vivophysiological conditions, the rate of phosphotransfer from EI to the second protein of the phosphotransferase system HPr by the dimer is much higher than by the monomer. A hypothesis is proposed on the basis of calculations that the transfer by a monomer plays a role in the regulation of chemotaxis. At submicromolar pyruvate concentration, the model predicts nonmonotonic dependence of the phosphotransfer rate on the substrate (PEP) concentration.