24R,25-dihydroxyvitamin D3 regulates 1,25-dihydroxyvitamin D3 binding to its chick intestinal receptor.
24R,25-dihydroxyvitamin D3 regulates 1,25-dihydroxyvitamin D3 binding to its chick intestinal receptor.
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24R,25-二羟基维生素 D3 调节 1,25-二羟基维生素 D3 与其小鸡肠道受体的结合。
DOI：
10.1016/0006-291x(85)90633-3
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发表时间：
1985
影响因子：
3.1
通讯作者：
Norman,AW
中科院分区：
文献类型：
--
作者：
Wilhelm,F;Norman,AW
我们研究了1，25-二羟维生素D3[1，25（OH）2D 3]与其粗染色质鸡肠受体的结合，在[3 H]-1，25（OH）2D 3的每种浓度下，不存在或存在10倍过量的24 R，25-二羟维生素D3[24 R，25（OH）2D 3]。我们已经发现，在过量的24 R，25（OH）2D 3存在下，1，25（OH）2D 3与其受体的结合发生了显著的右移。结果发现，亲和力显著降低，表观解离常数从0.97±0.09（n = 5）变化到1.36±0.04 nM（p < 0.01）。这种降低与1，25（OH）_2D_3与其受体结合的表观Hill系数从nH= 1.49±0.06显著降低到nH= 1.26±0.06（p < 0.03）有关。受体容量无显著变化（189±11与200±9 fmol/mg蛋白质相比）。这些结果表明，肠道1，25（OH）_2D_3受体也必须有一个24 R，25（OH）_2D_3的结合识别位点，该位点可能在1，25（OH）_2D_3受体的配体结合特性中起调节作用。
We have studied the binding of 1,25-dihydroxyvitamin D3[1,25(OH)2D3] to its crude chromatin chick intestinal receptor in the absence or presence of a ten-fold excess of 24R,25-dihydroxyvitamin D3[24R,25(OH)2D3] for each concentration of [3H]-1,25(OH)2D3studied. We have found a significant shift to the right in the binding of 1,25(OH)2D3to its receptor in the presence of this excess of 24R,25(OH)2D3. As a result, the affinity was found to be significantly reduced, the apparent dissociation constants varied from 0.97±0.09 (n = 5) to 1.36±0.04 nM (p < 0.01). This reduction was related to a significant decrease in the positive cooperativity for the apparent Hill coefficient from nH= 1.49±0.06 to nH= 1.26±0.06 (p < 0.03) in the binding of 1,25(OH)2D3to its receptor. There was no significant change in the capacity of the receptor (189±11 compared to 200±9 fmoles/mg protein). These results suggest that the intestinal 1,25(OH)2D3receptor must also have a binding recognition site for 24R,25(OH)2D3which is postulated to play a regulatory role in the 1,25(OH)2D3receptor's ligand binding properties.