Photoaffinity labeling of the human erythrocyte monosaccharide transporter with an aryl azide derivative of D-glucose.
A photoreactive, radioiodinated derivative of glucose, N-(4-iodoazidosalicyl)-6-amido-6-deoxyglucopyranose (IASA-glc), has been synthesized and used as a photoaffinity label for the human erythrocyte monosaccharide transporter. Photoinactivation and photoinsertion are both light-dependent and result in a marked decrease in the absorption spectra of the compound. When [125I]IASA-glc was photolyzed with erythrocyte ghost membranes, photoinsertion of radiolabel was observed in three major regions, spectrin, band 3, and a protein of 58,000 daltons located in the zone 4.5 region. Of the three regions which were photolabeled, only labeling of polypeptides in the zone 4.5 region was partially blocked by D-glucose. In the non-iodinated form, N-(4-azidosalicyl)-6-amido-6-deoxy-glucopyranose inhibited the labeling of the transporter by [125I]IASA-glc more effectively than D-glucose. The ability to synthesize this [125I]containing photoprobe for the monosaccharide transporter at carrier-free levels offers several new advantages for investigating the structure of this transport protein in the erythrocyte.
D000345:Affinity Labels / Q000138:chemical synthesis*; D001386:Azides / Q000138:chemical synthesis* / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism*; D002352:Carrier Proteins / Q000097:blood* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins
D000345:Affinity Labels; D001386:Azides; D001786:Blood Glucose; D002352:Carrier Proteins; D007457:Iodine Radioisotopes; D009004:Monosaccharide Transport Proteins; C046453:N-(4-iodoazidosalicyl)-6-amido-6-deoxyglucopyranose; D005944:Glucosamine