Covalent coupling of bovine growth hormone to its receptor in bovine liver membranes.
The structure of bovine somatotropin receptor was examined following covalent coupling of iodinated recombinant bovine growth hormone ([125I]rbGH) to bovine liver membrane receptors using ethylene glycol bis(succinimidyl succinate). Iodinated rbGH was incorporated into a complex of estimated Mr of 140,000 under reducing conditions. Excess unlabeled rbGH, but not bovine prolactin (bPRL), inhibited completely the incorporation of [125I]rbGH into the Mr = 140,000 species. In dairy bulls, the Mr = 140,000 complex was undetectable soon after birth but became predominant at 6 months of age. No evidence was found to support presence of bPRL receptors in steer liver membranes. Assuming a 1:1 stoichiometry of hormone binding to receptor, it appears that bGH binds to a major receptor subunit of Mr = 119,000 which does not recognize bPRL.
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D011986:Receptors, Somatotropin / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism*; D013388:Succinimides / Q000378:metabolism
D003432:Cross-Linking Reagents; D011986:Receptors, Somatotropin; D011994:Recombinant Proteins; D013388:Succinimides; C028722:ethylene glycolylbis(succinimidyl succinate); D013006:Growth Hormone