Disulfide bonds within the alpha-subunit of insulin receptors in rat liver and brain membranes.
We have characterized inter- and intrasubunit disulfide bonds of insulin receptors using reductant-treated rat liver and brain membranes. In autoradiograms of 125I-insulin cross-linked to both membranes pretreated with dithiothreitol, the intensity of affinity-labeled bands of the alpha beta-heterodimer and alpha-subunit was increased. Interestingly, labeled 120 and 110 kDa bands considered to be the alpha-subunit in partially reduced liver and brain membranes moved to 130 and 120 kDa bands under further reduced conditions, respectively. Double electrophoresis of each partially reduced band in the presence of reductants clearly demonstrates that the alpha-subunit of insulin receptors contains intrasubunit disulfide bonds.
D000818:Animals; D001921:Brain / Q000378:metabolism; D003432:Cross-Linking Reagents; D004220:Disulfides / Q000378:metabolism; D004229:Dithiothreitol; D008099:Liver / Q000378:metabolism; D008297:Male; D008566:Membranes / Q000378:metabolism; D011487:Protein Conformation; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000378:metabolism*
D003432:Cross-Linking Reagents; D004220:Disulfides; D011972:Receptor, Insulin; D004229:Dithiothreitol