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Characterization and properties of steroid binding protein in Bufo arenarum serum
Author(s) -
Fernández Silvia N.,
MansillaWhitacre Zulema C.,
Miceli Dora C.
Publication year - 1994
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080380403
Subject(s) - estrone , diethylstilbestrol , biology , estriol , steroid , binding site , binding protein , endocrinology , dihydrotestosterone , testosterone (patch) , medicine , androgen , biochemistry , hormone , gene
Serum steroid binding properties of mature Bufo arenarum females were studied. Binding data obtained using charcoal adsorption assay and equilibrium dialysis methods indicates a single protein, named Bufo arenarum sex binding protein (Ba SBP), which binds 5 α‐dihydrotestosterone (DHT), testosterone (T), and estradiol‐17β (E 2 ) with high affinity (10 7 M −1 – 10 8 M −1 ) and fair capacity (10 −6 M). Scatchard plot analysis demonstrated the coexistence of two binding sites. Ba SBP has a sedimentation coefficient of 5.2 S in sucrose gradient centrifugation in low salt and under steady‐state conditions. The specificity of this protein, determined by competitive binding experiments, is comparable to human SBP. DHT and T bind with higher affinity than E 2 . Estriol and estrone competed poorly, while diethylstilbestrol and C 21 steroids did not compete. The binding capacity of this protein is under estrogenic control. © 1994 Wiley‐Liss, Inc.