Photoaffinity labeling of the K562 cell membrane D-glucose transporter with cytochalasin B.
D-glucose carrier protein in K562 cell membrane was studied by photoaffinity labeling with cytochalasin B. The saturable cytochalasin B binding in purified K562 cell membranes was 90 pmol/mg and 200 pmol/mg protein in the presence of D-glucose and D-sorbitol, respectively. More than half of the total cytochalasin B binding could be depressed by D-glucose. The results of SDS-PAGE analysis of K562 cell membranes after photoaffinity labeling at 0.1 microM cytochalasin B showed that the main peak of covalently bound [3H]-cytochalasin B was in the Mr range of 46-65 KDa. The label found in the peak was reduced by more than 50% in the presence of 0.5 M D-glucose, the inhibition similar being to that obtained in the binding experiment. This polypeptide has a slightly higher molecular weight than that of the human erythrocyte cell membrane.
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D000345:Affinity Labels; D002458:Cell Fractionation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D003571:Cytochalasin B / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D007951:Leukemia, Myeloid; D009004:Monosaccharide Transport Proteins / Q000302:isolation & purification / Q000378:metabolism*
D000345:Affinity Labels; D009004:Monosaccharide Transport Proteins; D003571:Cytochalasin B; D005947:Glucose