Characterization and Solubilization of Gonadotropin Receptor of Bovine Corpus Luteum

摘要: Plasma membranes isolated from bovine corpora lutea showed specific binding with 125I-human chorionic gonadotropin and luteinizing hormone; unlabeled hormones competitively inhibited the binding. The of to receptor was a saturable phenomenon half-saturation attained at concentration 4 x 10-10 m . Maximum hormone obtained within 15 min pH 7.2 37°. rate constants association dissociation human determined 37° were 2.8 106 -1 s 2.1 10-5 -1, respectively. constant calculated these rates 8.0 At 4° extremely slow complex stable up 48 hours. equilibrium data be 1.5 for number sites approximately 6.3 10-15 per mg tissue. plasma optimum reduced acidic basic pH. also high concentrations CaCl2, MgCl2, NaCl, in presence guanidine HCl urea. inhibition 5 9 1 various ions reversible. Treatment membrane phospholipase C, neuraminidase, glucosidase, trypsin, α-chymotrypsin did not decrease gonadotropin. Pepsin A membranes. solubilized detergents. proteins reprecipitated solution by ethanol-ammonium acetate retained ability bind Solubilization 6 resulted separation protein lipid components. Fractionation component achieved gel filtration on column Sepharose 4B ion exchange chromatography DEAE-cellulose 3 activity purified fractions could reconstituted emulsification fraction, indicating requirement lipids retain native conformation receptor. molecular weight active material estimated polyacrylamide electrophoresis sodium dodecyl sulfate between 30,000 70,000. This partially may represent regulatory subunit