Removal of sialic acids from the purified insulin receptor results in enhanced insulin-binding and kinase activities.
Neuraminidase treatment of the purified insulin receptor resulted in an increase in both insulin-binding and kinase activities. Neuraminidase-treated alpha and beta subunits moved further than native subunits on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. The enhancement of insulin-binding and kinase activities and increased mobility of the subunits on SDS-PAGE were not observed when the receptor was treated with neuraminidase in the presence of neuraminidase inhibitor. These results suggest that terminal sialic acid residues have a significant role in insulin-binding and kinase activities. The involvement of sialic acid residues in the activities of the receptor has not been detected by previous studies.
D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D046911:Macromolecular Substances; D009438:Neuraminic Acids / Q000494:pharmacology; D009439:Neuraminidase / Q000378:metabolism; D011247:Pregnancy; D011494:Protein Kinases / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism*; D012794:Sialic Acids / Q000502:physiology*
D007328:Insulin; D046911:Macromolecular Substances; D009438:Neuraminic Acids; D012794:Sialic Acids; C045864:2,3-dehydroneuraminic acid; D011494:Protein Kinases; D011972:Receptor, Insulin; D009439:Neuraminidase