Boctor A M, Band P, Grossman A
Proc Natl Acad Sci U S A. 1981 Sep;78(9):5648-51. doi: 10.1073/pnas.78.9.5648.
Supernatant fractions from rat pancreas bind approximately 300 fmol of [3H]estradiol per mg of protein when incubated with 5 nM [3H]estradiol for 1 hr at room temperature. Passage through gel filtration columns reduces binding in the eluate to approximately 1% of its initial activity. Extracts of the supernatant contain a factor that reactivates binding in gel filtrates. Addition of accessory factor to fractional eluates gives one sharp peak of activity. Since fractions that cannot be reactivated contain as much or more protein as fractions that can be reactivated, it is concluded that interaction of accessory factor and [3H]estradiol-binding protein is specific. Peptides such as antipain [(1-carboxy-2-phenylethyl)carbamoyl-L-arginyl-L-valyl-L-argininal] and, especially, N-benzoyl-L-phenylalanyl-L-valyl-L-arginine-p-nitroanilide also enhanced binding of [3H]estradiol. Accessory factor is water soluble, dialyzable, and heat stable. Although as currently purified, it contains several substances, the data suggest that at least one component of accessory factor is an oligopeptide.
当在室温下与5 nM [³H]雌二醇孵育1小时时，大鼠胰腺的上清液组分每毫克蛋白质结合约300 fmol的[³H]雌二醇。通过凝胶过滤柱后，洗脱液中的结合活性降低至其初始活性的约1%。上清液提取物含有一种能使凝胶过滤物中的结合活性重新激活的因子。向分级洗脱液中添加辅助因子会产生一个尖锐的活性峰。由于无法重新激活的组分所含蛋白质与可重新激活的组分一样多或更多，因此得出结论，辅助因子与[³H]雌二醇结合蛋白的相互作用是特异性的。诸如抗蛋白酶[(1-羧基-2-苯乙基)氨基甲酰-L-精氨酰-L-缬氨酰-L-精氨醛]，尤其是N-苯甲酰-L-苯丙氨酰-L-缬氨酰-L-精氨酸对硝基苯胺等肽也增强了[³H]雌二醇的结合。辅助因子可溶于水、可透析且耐热。尽管按目前的纯化方法，它含有几种物质，但数据表明辅助因子的至少一种成分是一种寡肽。
