PURIFICATION OF THE SEX STEROID-BINDING PROTEIN FROM COMMON CARP (CYPRINUS-CARPIO) PLASMA

1. Sex steroid-binding protein was purified from common carp plasma. 2. Testosterone- and estradiol-binding activity existed at the same fraction eluted from gel Sepharose CL-2B, DEAE-Sephacel, hydroxylapatite and HPLC. 3. The molecular weight of the sex steroid-binding protein was 194,000. 4. At 50% displacement the order in which the steroids displaced [H-3]testosterone bound to the binding protein was a follows: androstenedione > estradiol-17-beta > 11-deoxy-17-hydroxycorticosterone > 17-alpha-hydroxyprogesterone > progesterone > deoxycorticosterone > estrone > 11-ketotestosterone > 17-alpha, 20-beta-dihydroxy-4-pregnen-3-one > androstenedione > pregnenolone > cortisone > cortisol.