Purification and characterization of the human ovarian LH/hCG receptor and comparison of the properties of mammalian LH/hCG receptors.
Methods previously published by us [Wimalasena et al., J Biol Chem 260: 10689-10697, 1985; Wimalasena et al., J Biol Chem 261: 9416-9420, 1986] were utilized to solubilize the human corpus luteal leuteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor with 3-[(3-cholamide-propyl)dimethylammonio]-1-propanesulfonate (CHAPS) and to purify the receptor by two steps of hCG-Sepharose affinity chromatography. The specific binding capacity (SBC) of the purified human receptor was 7510 pmol/mg protein, and KA = 2.2 x 10(9) M-1 when iodo hCG was competed by hCG; the yield was 4-7% of starting activity. When hLH was used in competition with hCG, specific binding capacity was 7900 pmol/mg protein and KA 1.0 x 10(9) M-1. Silver staining and autoradiography demonstrated a single protein of Mr 78,000 under reducing and Mr 58-62 x 10(3) under nonreducing conditions. Rat ovarian LH/hCG receptor was purified by similar methods and the KA of 3.5 x 10(10) M-1 for hCG was substantially different from the KA for hLH which was 2.1 x 10(9) M-1. Mr of the rat protein was 78-82 x 10(3) (reduced) and 58-62 x 10(3) (nonreduced) when analyzed by silver staining and autoradiography. For the first time, human LH/hCG receptor has been purified to apparent homogeneity, and its Mr of 78,000 was essentially identical to the Mr values of purified rat and porcine receptors.
Alpaugh
K
K
Department of Physiology, University of Nebraska Medical Center, Omaha 68105.
Indrapichate
K
K
Abel
J A
JA
Rimerman
R
R
Wimalasena
J
J
D000818:Animals; D002846:Chromatography, Affinity; D005260:Female; D006801:Humans; D008970:Molecular Weight; D010053:Ovary / Q000737:chemistry*; D051381:Rats; D011974:Receptors, LH / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D013045:Species Specificity; D013552:Swine
D011974:Receptors, LH