Q7 - Estimating Vmax and KM for GLUT1 Glucose Transport Kinetics
GLUT1, a protein present in the membrane of red blood cells, is a transporter that transports glucose into cells. The relationship between the extracellular glucose concentration (S) and the rate of glucose uptake (V) into red blood cells is shown in Figure 1. This relationship between V and S can be described by the Michaelis-Menten-like equation V = Vmax x S / (KM + S).
Figure 1.
Using the information and data, determine which of the statements are true or which are false.
Q7-1 Vmax. Estimate the approximate integer value for Vmax [nmol/min/cell] in the equation from the curve shown in Figure 1.
Q7-1 KM. Estimate the approximate integer value for KM [mM] in the equation from the curve shown in Figure 1.
A. Healthy humans typically have 4 to 6 mM of blood glucose. The rate of glucose transport per molecule by GLUT2 is considered to be approximately equal to that by GLUT4.
B. Although the transport rate of glucose by GLUT1 and GLUT4 is almost saturated in healthy humans, GLUT2 has an additional capacity to increase the transportation rate.
Question reproduced from IBO 2020, Theoretical Exam 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)