Minimal mathematical model of the energetic coupling of cotransport and anion-exchange mechanisms for transport in biological membranes
Orlov, I.N.; Rebane, I.T.; Rebane, E.N.
Biofizika 45(5): 857-863
2000
ISSN/ISBN: 0006-3029 PMID: 11094713 Document Number: 523068
A minimal model for the coupling of fluxes of two different anions was constructed, in which one anion Y, is transferred by both the cotransport and anion-exchange pathways, whereas the other anion, Z, only by the anion-exchange mechanism. The possibilities of the model for describing the cooperativity of cotransport and anion-exchange pathways are demonstrated by using the computer simulation approach. It is shown that the energetic coupling of Y and Z anion fluxes becomes possible when the following conditions are fulfilled: (1) The inward-directed flux of Y by the cotransport pathway exceeds its anion-exchange flux directed outward; (2) the reorientation probability of the Y-loaded anion-exchanger is higher than that of the unloaded exchanger.