Immunologic and steroid binding properties of the GCDFP-24 protein isolated from human breast gross cystic disease fluid.
A major protein of human breast cyst fluid, termed GCDFP-24, has the property of specifically binding progestins. The purified glycoprotein, of 24,000 apparent molecular weight, bound pregnenolone and progesterone with highest affinity. The association constant for binding of progesterone was 1 X 10(6)L/mol by Scatchard analysis, and there was one binding site per molecule. Changes to the progesterone structure at C-17, C-20, or C-21 interfered with binding. The pH optimum for binding was 4-4.5. The purified protein was highly stable and was not irreversibly denatured by 50% methanol or 3M guanidine. However, dithiothreitol reversibly interfered with progesterone binding. Rabbit antiserum produced against the glycoprotein recognized an immunologically identical component in normal human sera, and partially cross-reacting components in normal monkey and baboon sera. The component in human sera was present in Cohn fractions IV and VI.
Dilley
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WG
Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.
Haagensen
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Cox
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Wells
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D000818:Animals; D003429:Cross Reactions; D005260:Female; D005348:Fibrocystic Breast Disease / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D011284:Pregnenolone / Q000378:metabolism*; D011323:Primates / Q000097:blood; D011374:Progesterone / Q000378:metabolism*; D011485:Protein Binding
D007106:Immune Sera; D011374:Progesterone; D011284:Pregnenolone