Heyns W, Bossyns D, Peeters B, Rombauts W
J Biol Chem. 1982 Jul 10;257(13):7407-13.
A proline-rich polypeptide is associated with prostatic binding protein, a major androgen-dependent protein described previously in the rat ventral prostate. This polypeptide has been purified. Its molecular weight estimated by gel filtration is about 8500, but a markedly lower value (3300) is obtained by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis. Isoelectric focusing on thin layer polyacrylamide gels yields two major forms with isoelectric points of, respectively, 7.75 and 7.05. The amino acid composition of proline-rich polypeptide is characterized by a high (19.5%) proline content and its NH2-terminal amino acid is glycine. Like prostatic binding protein, proline-rich polypeptide is a characteristic component of the rat ventral prostate and localized primarily in the intraluminal secretion of this gland. In intact adult male rats the cytosol of a whole gland contains 0.70 +/- 0.15 (S.D.) mg of the polypeptide, as measured by radial immunodiffusion or 2.6 +/- 0.5% of (S.D.) of the total protein. This amount decreases gradually after castration and becomes undetectable after 8 days. Androgen treatment, on the other hand, results in a rapid stimulation, while estradiol and progesterone are ineffective. Proline-rich polypeptide is markedly more androgen-dependent than prostatic binding protein, and promises to be an interesting end point for studies on the mechanism of action of androgens.
一种富含脯氨酸的多肽与前列腺结合蛋白相关，前列腺结合蛋白是先前在大鼠腹侧前列腺中描述的一种主要的雄激素依赖性蛋白。这种多肽已被纯化。通过凝胶过滤估计其分子量约为8500，但通过十二烷基硫酸钠-尿素聚丙烯酰胺凝胶电泳得到的值明显较低（3300）。在薄层聚丙烯酰胺凝胶上进行等电聚焦产生两种主要形式，其等电点分别为7.75和7.05。富含脯氨酸的多肽的氨基酸组成的特征是脯氨酸含量高（19.5%），其氨基末端氨基酸是甘氨酸。与前列腺结合蛋白一样，富含脯氨酸的多肽是大鼠腹侧前列腺的特征性成分，主要定位于该腺体的腔内分泌物中。在完整的成年雄性大鼠中，通过放射免疫扩散测定，整个腺体的细胞溶质含有0.70±0.15（标准差）毫克的该多肽，占总蛋白的2.6±0.5%（标准差）。去势后该量逐渐减少，8天后变得不可检测。另一方面，雄激素治疗导致快速刺激，而雌二醇和孕酮则无效。富含脯氨酸的多肽比前列腺结合蛋白对雄激素的依赖性明显更强，有望成为研究雄激素作用机制的一个有趣的终点。
