A Kinetic Model of the Monocarboxylate Transporter MCT1 and its Interaction with Carbonic Anhydrase II
- *Corresponding Author:
- Joachim Almquist
Chalmers Science Park
SE-412 88 Göteborg, Sweden
E-mail: [email protected] fcc.chalmers.se
Received Date: October 26, 2010; Accepted Date: November 25, 2010; Published Date: November 27, 2010
Citation:Almquist J, Lang P, Prätzel-Wolters D, Deitmer JW, Jirstrand M, et al. (2010) A Kinetic Model of the Monocarboxylate Transporter MCT1 and its Interaction with Carbonic Anhydrase II. J Comput Sci Syst Biol 3:107-116. doi: 10.4172/jcsb.1000066
Copyright: © 2010 Almquist J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The enzyme carbonic anhydrase isoform II (CAII), catalyzing the hydration and dehydration of CO2, enhances transport activity of the monocarboxylate transporter isoform I (MCT1, SLC16A1) expressed in Xenopus oocytes by a mechanism that does not require CAII catalytic activity. In the present study, we have investigated the mechanism of the CAII induced increase in transport activity by using electrophysiological techniques and mathematical modeling of the MCT1 transport cycle. The model consists of six states arranged in cyclic fashion and features an ordered, mirrorsymmetric, binding mechanism, where binding and unbinding of the proton to the transport protein is considered to be the rate limiting step under physiological conditions. An explicit rate expression for the substrate flux is derived using model reduction techniques. By treating the pools of intra-and extracellular MCT1 substrates as dynamic states, the time dependent kinetics are obtained by integration, using the derived expression for the substrate flux. The simulations were compared with experimental data obtained from MCT1-expressing oocytes injected with different amounts of CAII. The model suggests that CAII increases the effective rate constants of the proton reactions, possibly by working as a proton antenna.