Aquaporin (AQUA1) transport H₂O orders of magnitude faster across the erythrocyte plasma membrane than GLUT1 transports glucose because: AQUA1 does not undergo any conformational change while transporting water molecules whereas GLUT1 does and therefore has lesser Vmax.
Aquaporin is a transmembrane protein that transports water molecules across the membrane. These are the passive channel proteins, thus they do not have to undergo any conformational change while transporting the molecules.
GLUT1 is a glucose transporter that is a carrier protein performing facilitated transport. It can be abundantly found in RBCs and brain tissues. Since it is facilitated transport, the glucose is transported down its concentration gradient.
