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

The mathematical model of the operation of the first enzyme of the Escherichia coli phosphotransferase 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 both in vivo physiological conditions and in vitro nonphysiological conditions. The model predicts that under in vivo physiological 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.

[A study of the regulation of photosynthesis by the analysis of the effect of kinetic parameters on the characteristics of the oscillatory regime and the rate of CO2 assimilation].

Earlier at the biophysics department, the experimental data on the oscillations of delayed luminescence have been described with the help of a mathematical model. Here we studied the influence of the model parameters on the characteristics of the oscillatory regime. The frequencies and damping factors of the oscillations at different parameter values were calculated using the Lyapunov analysis. It was shown that, in addition to oscillations observed experimentally, other, rapidly damping oscillations may exist. The dependence of the CO2 assimilation rate on the model parameters was studied. It was shown that the intensity of the light absorbed by photosystems I and II may differently affect the assimilation of CO2.

[A mathematical model of delayed luminescence oscillations of higher plants and analysis of the reaction rates calculated by the model].

The oscillatory regime of delayed millisecond luminescence was obtained by the model developed earlier. We compared the rates of changes in the concentrations of some of the metabolites calculated by the model with the rates calculated by other known models. The results of calculations for the changes in metabolite concentrations after switching off the light were compared with experimental data.