Heyns W, Bossyns D
J Steroid Biochem. 1983 Dec;19(6):1689-94. doi: 10.1016/0022-4731(83)90345-x.
The binding of estramustine, a nitrogen mustard derivative of oestradiol to purified rat prostatic binding protein was studied as a test for a possible identity between this protein and the very similar estramustine-binding protein, described by Forsgren et al. In accordance with this hypothesis estramustine binds to purified prostatic binding protein with a high affinity (2.5 X 10(7)M-1). This affinity markedly exceeds the affinity of pregnenolone for this protein (0.9 X 10(6)M-1) or for a complex of prostatic binding protein, with prostatic proline-rich polypeptide, (4.7 X 10(6)M-1). In competition experiments estramustine completely suppresses the binding of [3H]pregnenolone, whereas the binding of [3H]estramustine is only partially suppressed by pregnenolone, even at high concentrations. Prostatic binding protein was separated in its F- and S-subunit by DEAE-Sepharose chromatography performed in the presence of 8 M urea. Only the S-subunit, most probably in its dimer form, displays marked estramustine and pregnenolone binding, with affinities of respectively 3.7 and 1.2 X 10(6)M-1. Recombination of both subunits results in a strong increase of estramustine binding, but not of pregnenolone binding.
研究了雌二醇氮芥衍生物雌莫司汀与纯化的大鼠前列腺结合蛋白的结合情况，以此作为该蛋白与Forsgren等人描述的非常相似的雌莫司汀结合蛋白可能具有同一性的一项测试。根据这一假设，雌莫司汀以高亲和力（2.5×10⁷M⁻¹）与纯化的前列腺结合蛋白结合。这种亲和力明显超过孕烯醇酮与该蛋白的亲和力（0.9×10⁶M⁻¹），或与前列腺富含脯氨酸多肽的前列腺结合蛋白复合物的亲和力（4.7×10⁶M⁻¹）。在竞争实验中，雌莫司汀完全抑制[³H]孕烯醇酮的结合，而即使在高浓度下，孕烯醇酮也只能部分抑制[³H]雌莫司汀的结合。通过在8M尿素存在下进行的DEAE - 琼脂糖色谱法将前列腺结合蛋白分离为其F亚基和S亚基。只有S亚基，很可能以其二聚体形式，显示出明显的雌莫司汀和孕烯醇酮结合，亲和力分别为3.7×10⁶M⁻¹和1.2×10⁶M⁻¹。两个亚基的重组导致雌莫司汀结合力大幅增加，但孕烯醇酮结合力没有增加。
