Phlorizin-receptor interactions in fat cell plasma membranes

The rate but not the extent of phlorizin binding to purified fat cell plasma membranes was temperature dependent and this binding was a saturable process. A Scatchard plot revealed a population of sites which exhibited a dissociation constant of about 0.35 mM and a maximum binding capacity of about 8 nmoles/mg membrane protein. Under the conditions of these experiments neither glucose, phloretin, nor cytochalasin B inhibited ³H]phlorizin binding. These data demonstrate the presence in fat cell plasma membrane of specific receptors for phlorizin which may mediate the inhibitory effects of this agent on hexose trasport.