Photolabeling of the adipocyte hexose carrier with an aryl azide derivative of maltose.
A nitrophenyl azide derivative of maltose, N-(4-azido-2-nitrophenyl)-maltosylamine (NAP-maltosylamine), was synthesized as a potential photoaffinity label for the hexose carrier of the rat adipocyte. This derivative inhibited 3-O-methylglucose uptake with a Ki of 1.3 mM in the dark, while that of maltose was 10.0 mM. Carbon-14-labeled maltose and NAP-maltosylamine entered adipocytes via the hexose carrier, the latter in a concentrative fashion. Photolysis of NAP-[14C]maltosylamine in the presence of an adipocyte low density microsomal membrane fraction labeled several electrophoretic bands. Among these are a 45 kDa band which showed features expected of the hexose carrier: its labeling was decreased 40% by D- but not L-glucose and pretreatment of intact adipocytes with insulin decreased labeling of the 45 kDa band by 10-40%, as predicted by the translocation theory of insulin-stimulated transport activation. These studies show the suitability of using carbon-1-modified sugar photoaffinity labels as probes for the hexose carrier and possibly of its regulation in rat adipocytes.
D000273:Adipose Tissue / Q000378:metabolism*; D000345:Affinity Labels; D000606:Amino Sugars / Q000138:chemical synthesis / Q000378:metabolism; D000818:Animals; D001386:Azides / Q000138:chemical synthesis / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D008297:Male; D008320:Maltose / Q000031:analogs & derivatives; D008565:Membrane Proteins / Q000378:metabolism; D008757:Methylglucosides / Q000378:metabolism; D008970:Molecular Weight; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D010777:Photochemistry; D051381:Rats
D000345:Affinity Labels; D000606:Amino Sugars; D001386:Azides; D008565:Membrane Proteins; D008757:Methylglucosides; D009004:Monosaccharide Transport Proteins; C051946:N-(4-azido-2-nitrophenyl)maltosylamine; D008320:Maltose