Characteristics of a solubilized thyrotropin receptor from bovine thyroid plasma membranes.

摘要: The thyrotropin receptor from bovine thyroid plasma membranes has been solubilized using lithium diiodosalicylate, and an assay to measure binding the developed. Both on have effectively identical nonlinear Scatchard plots negatively sloped Hill plots, i.e. both preparations receptors which appear exhibit a similar cooperative relationship. Although pH optimum of is same as that membrane receptor, 6.0, dependency curve slightly different in its outline. Thyrotropin less sensitive salt inhibition than receptor; however, optimal remains at 0 degrees. relative affinities two glycoprotein hormones can be considered structural analogs, luteinizing hormone human chorionic gonadotropin, are 100:10:5, respectively, toward receptors, but 100:25:40 receptors. preparation heterogeneous size it components with molecular weights 286,000, 160,000, 75,000, 15,000 30,000. Tryptic digestion converts all three higher weight 30,000 species, component properties before tryptic including plot. It coelutes Sephadex G-100 released by or dog cells culture. fragment purified almost 250-fold affinity chromatography thyrotropin-Sepharose columns. activity lost when exposed beads neuraminidase-Sepharose conconavalin A-Sepharose.