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Two solute transporter models.

These models are similar to the one solute transporter models. Constants are given for binding rates of the solute to the transporter, as well as unbinding rates (kon A1 and koff A1). We can assume transporter concentrations are negligible relative to the solute concentration. Transmembrane flip rates are also provided. However, these models have two solutes competing in two compartments. Solutes A and B both are transported across the membrane. In the second chamber, A is reacted to form B in an enzymatic reaction approximated by a Michaelis-Menten expression.

Like enzymatic reactions, the flux is bidirectional. Unlike enzymes the "substrate" and "product" are identical. Unlike enzymes there is sidedness, and the substrate can be bound on either side of the membrane. Since in actuality a transporter molecule exposes its active site to only one side at a time, the transmembrane flip rate provides the driving force for the particular flux tat arises at certain concentrations. These models also show countertransporter facilitation/inhibition.

Relevant Equations here.

Two solute Transporter Models:

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Copyright (C) 1999-2009 University of Washington. From the National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061. Academic use is unrestricted. Software may be copied so long as this copyright notice is included. This software was developed with support from NIH grant HL073598. Please cite this grant in any publication for which this software is used and send one reprint to the address given above.

Key Terms

One solute, transmembrane flip rates, binding rates, facilitated transport.

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Model development and archiving support at provided by the following grants: NIH U01HL122199 Analyzing the Cardiac Power Grid, 09/15/2015 - 05/31/2020, NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.