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:
- Two solute, 2 region, with enzymatic conversion.
- Two solute, 2 region, with enzymatic conversion and flow.
- Two solute, 2 region, axially distributed, with enzymatic conversion, and flow.
References
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Key Terms
One solute, transmembrane flip rates, binding rates, facilitated transport.
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