Characterization of the metal ion requirement for oxytocin-receptor interaction in rat mammary gland membranes.
Characterization of the metal ion requirement for oxytocin-receptor interaction in rat mammary gland membranes.
复制标题
大鼠乳腺膜中催产素-受体相互作用所需金属离子的表征。
DOI：
10.1016/s0021-9258(18)50672-4
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
M. Soloff
中科院分区：
文献类型：
--
作者：
A. Pearlmutter;M. Soloff
二价阳离子的存在下是必不可少的[3 H]催产素的特异性结合颗粒受体制剂的哺乳期大鼠的乳腺。催产素的结合增强二价锌，镁，镍，锰和钴，但在二价钙，铜和铁的存在下可以忽略不计的顺序。在最佳浓度下，催产素/受体相互作用的表观Ka值。金属离子的浓度范围为3.1 - 8.6 × 108 M-1。金属离子并没有影响催产素受体之间的网站，网站之间的相互作用，证明了线性Scatchard图，希尔系数。的1，以及未结合的催产素对催产素/受体复合物的解离速率常数缺乏影响。激素/受体复合物的结合和解离的动力学表明，金属离子的结合是一个快速步骤，随后是催产素结合的缓慢速率决定步骤。活性二价金属离子似乎通过2个独立的过程影响催产素结合：（a）增加浓度;二价Ni、Mg、Mn的加入使合金中Ni、Mg、Mn的含量增加。（B）增加Co的量可增加催产素受体位点的亲和力，但不影响催产素的浓度。催产素结合的位点。因为max的组合。浓度的这两种类型的金属离子的浓度不是加和的。和催产素结合位点的亲和力，金属离子似乎结合到相同的位点。
The presence of a divalent cation is essential for the specific binding of [3H]oxytocin to particulate receptor preparations of the mammary gland of the lactating rat. Oxytocin binding was potentiated in increasing order by divalent Zn, Mg, Ni, Mn and Co, but was negligible in the presence of divalent Ca, Cu and Fe. The apparent Ka values for oxytocin/receptor interaction in the presence of optimal concn. of metal ions ranged from 3.1 to 8.6 X 108 M-1. The metal ions did not affect site-site interactions among oxytocin receptors, as evidenced by linear Scatchard plots, Hill coeff. of 1, and the lack of effect of unbound oxytocin on the dissociation rate constant of the oxytocin/receptor complex. The kinetics of the association and dissociation of the hormone/receptor complex showed a fast step for the binding of metal ion followed by a slow rate-determining step for the binding of oxytocin. The active divalent metal ions appeared to affect oxytocin binding by 2 separate processes; (a) increasing concn. of divalent Ni, Mg and Mn caused an increase in the concn. of binding sites available for oxytocin, while the affinity for the hormone was not changed; (b) increasing amounts of Co increased the affinity of the receptor site for oxytocin, but did not affect the concn. of sites available for oxytocin binding. Because combinations of max. concn. of both types of metal ions were not additive with respect to the concn. and affinity of oxytocin-binding sites, metal ions appear to bind to identical sites.