D-GLUCOSE TRANSPORTER ON MUSSEL MANTLE CELL-MEMBRANES - EFFECT OF SODIUM AND PHLORHIZIN

We studied the kinetics of the glucose transporter in mussel mantle ce lls. The transport is sodium dependent, with a very low uptake of gluc ose when sodium is replaced with potassium, choline or sucrose. In the presence of phlorizin, a glucose transporter inhibitor, the uptake is greatly diminished, with a low glucose uptake which is probably due t o passive diffusion. The Woolf-Augustinsson-Hofstee plot obtained with different concentrations of glucose, and the Hill coefficient obtaine d in studies about the effect of Na+ on glucose uptake, indicate that more than one sodium ion was involved in the transport of each molecul e of glucose across the membrane in mussel mantle cells, or that posit ive cooperativity is occurring. The activity of the transporter is not affected by the sodium-proton pump inhibitor amiloride. (C) 1993 Wile y-Liss, Inc.