Uptake and binding of dissaccharides in human erythrocytes

Disaccharides (sucrose, lactose, melibiose, cellobiose, trehalose, maltose, and isomaltose) are not transported across the human erythrocyte membrane. Maltose alone is bound in appreciable amounts to the intact cell as well as ghost membranes and competes mutually for uptake with D-glucose. In (NH4)2-SO4-precipitated membrane preparations, maltose binds more strongly than other disaccharides (KD = 1.3 X 10(-5) M; maximum binding capacity, 71 pmol/mg protein) and again competes mutually with D-glucose. Phloretin inhibits the binding of glucose much more than that of maltose.