title: Solubilization and purification of the gonadotropin (GTH II) receptor from rainbow trout (Oncorhynchus mykiss) ovaries.
abstract: The rainbow trout (Oncorhynchus mykiss) ovarian gonadotropin (GTH II) receptor was solubilized by extraction with the nonionic detergent 1% Triton X-100 in the presence of 20% glycerol. The hormone-binding characteristics of the soluble receptors were similar to those of membrane-bound receptors: the Scatchard plot of the equilibrium binding data produced a straight line, suggesting that the solubilized GTH II receptors, like membrane-bound receptors, contained a single class of high affinity 125I-sGTH II binding sites with an association constant of 2-5 x 10(10) M-1 (Ka = 1.4-2 x 10(10) M-1 for membrane-bound receptor). The maximal binding capacity was very low and varied from 7 to 17 fmol/mg proteins (about 5 fmol/mg ovarian membrane protein). The soluble receptor was purified by a simple and rapid immunoaffinity chromatography. The sGTH II-solubilized receptor complex was adsorbed to anti-sGTH II beta-subunit gammaglobulins covalently linked to Sepharose 4B and then eluted with an acidic buffer. About 50% of the binding activity present in the Triton X-100 extract was recovered in the pH 4 eluate. The other binding sites were eluted as a hormone-receptor complex and/or a damaged form. The free purified receptor presented a Ka of 1.3 x 10(10) M-1 in agreement with those found in membrane preparation and solubilized extract.
authors.affiliation: Laboratoire de Physiologie des Poissons, INRA, Campus de Beaulieu, Rennes, France.
authors.forename: H
authors.initials: H
authors.lastname: Quesnel
authors.forename: B
authors.initials: B
authors.lastname: Breton
mesh_terms: D000818:Animals; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D005260:Female; D007457:Iodine Radioisotopes; D007700:Kinetics; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010053:Ovary / Q000378:metabolism*; D011967:Receptors, Gonadotropin / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D011967:Receptors, Gonadotropin