Solubilization and partial characterization of the sex hormone-binding globulin receptor from human prostate.
The sex hormone-binding globulin (SHBG) receptor was solubilized from the membranes of human prostate glands with the zwitterionic detergent CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonic acid). The binding activity of the soluble receptor was measured by allowing it to bind to 125I-SHBG and precipitating the complex with polyethylene glycol-8000. The binding activity was stable for at least 4 months at -20 degrees C and had a half-life of 23 days at 4 degrees C. Like the membrane-bound receptor, Scatchard analysis revealed two sets of binding sites for the soluble one. At equilibrium (24 h), the high affinity site had an association constant (KA) of 6.8 x 10(8) M-1 and a binding capacity of 1.4 pmol/mg protein, whereas the low affinity site had a KA of 4.7 x 10(6) M-1 and a binding capacity of 43 pmol/mg protein. At 37 degrees C, the association rate constant (k1) was 8.37 x 10(5) M-1 min-1 and the dissociation rate constant (k2) was 3.43 x 10(-4) min-1. The soluble receptor was retarded on Sepharose CL-6B and had an apparent Mr = 167,000.
Hryb
D J
DJ
Department of Medicine, St. Luke's/Roosevelt Hospital Center, College of Physicians and Surgeons, Columbia University, New York, New York 10019.
Khan
M S
MS
Romas
N A
NA
Rosner
W
W
D002793:Cholic Acids; D002850:Chromatography, Gel; D003902:Detergents; D004355:Drug Stability; D006801:Humans; D007700:Kinetics; D008297:Male; D011092:Polyethylene Glycols; D011467:Prostate / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000302:isolation & purification* / Q000378:metabolism; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D012995:Solubility
D002793:Cholic Acids; D003902:Detergents; D011956:Receptors, Cell Surface; D012738:Sex Hormone-Binding Globulin; D011092:Polyethylene Glycols; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate