Smirnov A N
Biokhimiia. 1989 Jul;54(7):1108-19.
The estrophilic fraction of hydroxysteroid dehydrogenase (HSD) from the soluble fraction of rabbit liver was purified by ammonium sulfate precipitation, gel filtration, ion-exchange chromatography and affinity chromatography on estradiol-Sepharose. The isolated protein preparation expresses the 3 alpha-, 3 beta-, 17 beta- and 20 alpha-HSD activities on androgen and progestogen substrates. Some characteristics of 3H-estradiol, 3H-testosterone and 3H-progesterone interaction with the protein, the mutual competition of these hormones and the competitive efficiency of 73 steroids and their analogs in experiments with 3H-progesterone were investigated. It was found that sex steroids of all the three groups interact with a moderate affinity with the isolated HSD (K alpha approximately 10(7) M-1 at 0-4 degrees C). This interaction is characterized by relatively high association and dissociation rates. The main structural determinants of steroid ligands which provide for their affinity for the protein were established. The experimental results suggest that androgens and progestogens interact with the same binding site of the protein, whereas estrogens interact with a different site. It is supposed that by virtue of its high affinity for steroids and high concentration in the cells, the isolated protein can accomplish not only the enzymatic, but also a steromodulin function via reversible interactions with steroid ligands.
通过硫酸铵沉淀、凝胶过滤、离子交换色谱以及在雌二醇-琼脂糖上的亲和色谱，从兔肝可溶性部分中纯化出了羟基类固醇脱氢酶（HSD）的嗜雌激素部分。分离得到的蛋白质制剂对雄激素和孕激素底物表现出3α-、3β-、17β-和20α-HSD活性。研究了3H-雌二醇、3H-睾酮和3H-孕酮与该蛋白质相互作用的一些特性、这些激素之间的相互竞争以及73种类固醇及其类似物在3H-孕酮实验中的竞争效率。结果发现，所有三组性类固醇与分离出的HSD以中等亲和力相互作用（在0-4℃时Kα约为10(7) M-1）。这种相互作用的特点是缔合和解离速率相对较高。确定了类固醇配体对该蛋白质具有亲和力的主要结构决定因素。实验结果表明，雄激素和孕激素与蛋白质的同一结合位点相互作用，而雌激素与不同位点相互作用。据推测，由于其对类固醇的高亲和力和在细胞中的高浓度，分离出的蛋白质不仅可以通过与类固醇配体的可逆相互作用完成酶促功能，还可以完成类固醇调节蛋白的功能。
