Figure 6. The (Pi/Po)-dependences of [glucoseo]min for rSGLT1 (from Fig. 5) and for GLUT1.
Equation (4) was used, with the intracellular glucose concentration, [glucosei], the membrane potential, Em,oi, and Po held fixed at 2 μM, −91 mV, and 1 atm, respectively (T = 310 K). The regions of Na+ electrochemical and H2O barochemical dominance are very evident. Influx through the rSGLT1 transporter is much more sensitive to Pi/Po than that (barely noticeable) through the GLUT1 transporter. This is due to the much greater water stoichiometry of the former (Fig. 1).