Notides A C, Weichman B M, Lerner N, de Boer W
Adv Exp Med Biol. 1979;117:297-307. doi: 10.1007/978-1-4757-6589-2_16.
The dissociation of estradiol from the estrogen receptor occurs in two kinetic phases: a fast component having a half-time of approximately 3 min and a slower, or second, dissociating component having a half-time of approximately 95 min at 28 degrees. The fast component is produced by the dissociation of estradiol from the nonactivated 4 S receptor, a monomer. Thus, the magnitude of the fast component of the [3H] estradiol biphasic dissociation curve is proportional to the fraction of the receptor in the nonactivated state. The slow component is the estradiol dissociating from the activated 5 S receptor, a dimer. The salt-extracted estrogen receptor isolated from uterine nuclei shows a single, slow dissociating component equal to the slower component of the cytoplasmic biphasic dissociation curve. Estradiol binding shifts the receptor equilibrium from the low affinity nonactivated 4 S receptor toward the high affinity activated 5 S receptor. The kinetics of estriol dissociation from the receptor shows a larger fractional magnitude for the fast component and a faster second dissociating component than estradiol. This suggests that estriol transforms a smaller fraction of the receptor to the activated state and that the activated estriol receptor has a shorter half-time than estradiol. The biphasic dissociation kinetics of an estrogen from the receptor provides a new and sensitive criterion for measuring receptor activation.
一个快速成分，半衰期约为3分钟；另一个较慢的或第二个解离成分，在28摄氏度时半衰期约为95分钟。快速成分是由雌二醇从非活化的4S受体（一种单体）上解离产生的。因此，[3H]雌二醇双相解离曲线的快速成分的大小与处于非活化状态的受体比例成正比。慢速成分是雌二醇从活化的5S受体（一种二聚体）上解离。从子宫核中分离出的经盐提取的雌激素受体显示出单一的、慢速解离成分，等同于细胞质双相解离曲线的较慢成分。雌二醇结合使受体平衡从低亲和力的非活化4S受体向高亲和力的活化5S受体转移。雌三醇从受体上解离的动力学显示，快速成分的分数幅度比雌二醇大，第二个解离成分比雌二醇快。这表明雌三醇将较小比例的受体转化为活化状态，且活化的雌三醇受体的半衰期比雌二醇短。雌激素从受体上的双相解离动力学为测量受体活化提供了一个新的、灵敏的标准。
