Model number

Models a two compartment, 2 solute, T1-T2 (facilitated 6-state transporter with effective PS calculation. Directly related to model Transp2sol.Comp2 (model #10).


   Transp2sol.Comp2.PS is a six state transporter model for 2 solutes in 
 which compete for the transporter site on both sides of a membrane
 between two instantaneously mixed compartments. In comparmtment 2, A 
 is reacted to form B in an enzymatic reaction approximated by a 
 Michaelis-Menten expression without any accounting for binding of 
 solutes to the enzyme. When the rates of conformational state change 
 for transmembrane flipping of TA and TB are high compared to that for uncomplexed 
 transporter T, or if Kds for the transporter binding are low compared to the 
 substrate concentrations, then the model behaves much like an obligatory 
 countertransporter, exchanging B for A across the membrane. 

   This secondary model (See Transp2.sol.Comp2 for more detail) has a 
 Michaelis-Menten PS term (MMA1, MMA2) which is valid when assuming the 
 transporter (T) has high on- and off rates and transmembrane flipping is 
 considered instantaneous. Use the MMA2 parameter for comparison to A2. 

fig 1


The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.

Download JSim model project file

Help running a JSim model.

 Klingenberg M. Membrane protein oligomeric structure and transport function. Nature 290: 449-454, 1981.

 Stein WD. The Movement of Molecules across Cell Membranes. New York: Academic Press, 1967.

 Stein WD. Transport and Diffusion across Cell Membranes. Orlando, Florida: Academic Press Inc., 1986.

 Wilbrandt W and Rosenberg T. The concept of carrier transport and its corollaries in pharmacology. 
 Pharmacol Rev 13: 109-183, 1961.

 Schwartz LM, Bukowski TR, Ploger JD, and Bassingthwaighte JB. Endothelial adenosin transporter 
 characterization in perfused guinea pig hearts. Am J Physiol Heart Circ Physiol 279: H1502-H1511, 2000.

 Foster DM and Jacquez JA. An analysis of the adequacy of the asymmetric carrier model for sugar 
 transport. Biochim Biophys Acta 436: 210-221, 1976. 
Key terms
Two solutes
competing solutes
enzymatic reaction
transmembrane flip
six state transporter
two compartment
effective PS

Please cite in any publication for which this software is used and send one reprint to the address given below:
The National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061.

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.