MATHEMATICAL SIMULATION OF THE LIGHT-INDU CED UPTAKE OF PROTONS BY CHLOROPLASTS UPON VARIOUS MECHANISMS OF PROTON LEAK THROUGH THE THYLAKOID MEMBRANE

The processes of proton uptake by chloroplasts and light-induced acidi fication of intrathylakoid volume were simulated within. the frame of the model which takes into account the proton influx due to the protol ytic reactions of water splitting by PS2 and plastoquinol oxidation by b/f complex. The proton efflux from the thylakoids was calculated usi ng three different functions of proton leakage. It has been shown that the model of proton efflux across the thylakoid membrane, which is re lied on the mechanism of proton exchange with intramembrane proton-acc epting group, provides the most realistic description of experimental dependencies of the internal pH(in) and the number of protons consumed by the thylakoids versus external pH(out).