Analysis of estrogen receptor activation by its [3H]estradiol dissociation kinetics.
Analysis of estrogen receptor activation by its [3H]estradiol dissociation kinetics.
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通过[3H]雌二醇解离动力学分析雌激素受体激活。
DOI：
10.1021/bi00568a034
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发表时间：
1979
期刊：
影响因子：
2.9
通讯作者：
A. Notides
中科院分区：
文献类型：
--
作者：
B. Weichman;A. Notides
摘要：[3EI(雌二醇)从小牛子宫的雌激素受体上解离遵循一个双组分的指数过程。快成分归因于[~3H]雌二醇从非激活受体上解离，其速率常数为快成分的大小与处于非激活状态的受体比例成正比。慢指数成分k.2代表[~3H]雌二醇从激活的受体上解离。在含有0.4Mk的缓冲液中。当受体浓度为3.6、1.7和0.8 nM时，快成分在28℃时的振幅分别为0.10、0.13和0.23，在无(k.=0.18min‘；k2=7.0×10~(-3)tnin~(-1))或存在0.4mkc1(C.)时，解离速率常数相似；K-2=8.3×10“3min-1)。受体从低亲和力状态到高亲和力(激活)状态的转变直接依赖于非激活受体的浓度；浓度越大，快成分的幅度越小。硫酸铵沉淀后，雌二醇从受体上解离为单相，其速率常数为7.7×10~3min‘，与双相曲线的k2一致，蔗糖梯度分析表明存在激活的5S受体。在0.1-0.4M硫氰酸钠存在下，[~3H]雌二醇的解离为单指数过程，速率常数随硫氰酸钠浓度的增加而增大。将pH从6.8增加到8.0会导致快分量的大小从0.44下降
Barry M. Weichman and Angelo C. Notides* abstract: The dissociation of [3EI (estradiol from the estrogen receptor of the calf uterus follows a two-component exponential process. The fast component is ascribed to [3H] estradiol dissociating from the nonactivated receptor, and its rate constant is the magnitude of the fast component is proportional to the fraction of the receptor in the nonactivated state. The slow exponential component, k. 2, represents the [3H] estradiol dissociating from the activated receptor. In buffer containing 0.4 Mk. C1 the magnitude of the fast component was inversely proportional to the initial receptor concentration; at a [3H] estradiol receptor concentration of 3.6, 1.7, and 0.8 nM, the amplitude of the fast component at 28 C was 0.10, 0.13, and 0.23, respectively, The dissociation rate constants were similar in the absence (k..¡= 0.18 min'; k_2= 7.0 X 10 “3 tnin" 1) or presence of 0.4 Mkc1 (C.,= 0.14 min-1; k-2= 8.3 X 10" 3 min-1). The transformation of the receptor from the low to the higher affinity (activated) state is directly dependent upon the concentration of the nonac-tivated receptor present; the greater the concentration, the smaller the magnitude of the fast component. The dissociation of [3H] estradiol fromthe receptor following ammonium sulfate precipitation is monophasic, with a rate constant (7.7 X 10 3 min') identical with k 2 of the biphasic curve; sucrose gradient analysis showed the presence of the activated 5S receptor. In the presence of 0.1-0.4 M sodium thiocyanate,[3H] estradiol dissociation occurred as a single exponential process, with an increase in the rate constant as the NaSCN concentration increased. Increasing the pH from 6.8 to 8.0 resulted in a decrease in the magnitude of the fast component from 0.44