Glucose transport carrier in human erythrocyte membranes. Dinitrophenylation of a membrane component modified by D-glucose.

The effect of D-glucose on dinitrophenylation of membrane proteins of human erythrocyte ghosts by 1-fluoro-2,4-dinitrobenzene was studied in the absence and in the presence of D-glucose. A double isotopic, differential labeling technique followed by gel electrophoresis of extracts in the presence of sodium dodecyl sulfate revealed the presence of a polypeptide, or polypeptides, in human erythrocyte membranes, the reactivity of which to 1-fluoro-2,4-dinitrobenzene was significantly enhanced in the presence of D-glucose. Molecular weights of the peptides were estimated to be approximately 180,000. The effective differential labeling of the peptides required specific conditions identical with the ones which maximize the differential between inactivation of the carrier by 1-fluoro-2,4-dinitrobenzene and the dinitrophenylation of bulk membrane (Jung, C. Y. (1974) J. Biol. Chem. 249, 3568). A differential labeling was also demonstrated as a single peak by LH-20 column chromatography of chloroform-methanol-extractable membrane components. The peak contained both protein and phospholipids, indicating its proteolipid-like nature. A possible relationship of the differentially labeled polypeptides to the glucose carrier is discussed.