Peptide mapping of the insulin-binding site of the 130-kDa subunit of the insulin receptor by means of a novel cleavable radioactive photoprobe.
A radioactive photoaffinity probe for the insulin receptor was prepared by derivatizing insulin at its B29 lysine with a novel crosslinking reagent having a cleavable azo linkage. Insulin receptors purified from human placental membranes were photoaffinity labeled with this probe. The photolabeled receptor was treated with dithionite to cleave the azo linkage, thereby removing the insulin ligand and transferring the radioactivity to the receptor protein. The radioactive labeled subunit was isolated and digested with elastase for peptide mapping and separation by high performance liquid chromatography. Results obtained indicated that it will be feasible to use this new photoaffinity probe to obtain radioactive peptides representing the insulin-binding site(s) on the receptor subunit.
D000345:Affinity Labels; D000595:Amino Acid Sequence; D001345:Autoradiography; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008027:Light; D010920:Placenta / Q000032:analysis; D011247:Pregnancy; D011972:Receptor, Insulin / Q000032:analysis*
D000345:Affinity Labels; D007457:Iodine Radioisotopes; D011972:Receptor, Insulin