Biochemical properties of the 1 alpha, 25-dihydroxyvitamin D3 cytosol receptors from human and chicken intestinal mucosa.
Biochemical properties of the 1 alpha, 25-dihydroxyvitamin D3 cytosol receptors from human and chicken intestinal mucosa.
复制标题
人和鸡肠粘膜 1 α, 25-二羟基维生素 D3 胞质受体的生化特性。
DOI：
--
复制
发表时间：
1980
影响因子：
5.8
通讯作者：
A. Norman
中科院分区：
文献类型：
--
作者：
W. Wecksler;F. Ross;R. Mason;A. Norman
1 α，25-二羟基维生素D3的特异性细胞质受体显示存在于人肠胞质溶胶中，其非常类似于存在于鸡肠胞质溶胶中的类似1 α，25-二羟基维生素D3受体。两种受体都是3.5S蛋白，在低离子强度条件下聚集。它们的分子量约为60，000，斯托克斯分子半径为33。在4 ℃时，受体的平衡解离常数均为2 × 10 ~（-10）M.在0 ℃时，人受体的结合速率常数为2.5 × 10（7）M-1 min-1，而鸡受体的结合速率常数为0.5 × 10（7）M-1 min-1。在4 ℃下的解离速率常数为6.4 × 10（-4）min-1（人）和3.6 × 10（-5）min-1（鸡）.此外，发现两种受体在1 α，25-二羟基维生素D3结合位点附近具有还原的半胱氨酸残基，这对受体结合活性至关重要。人类和鸡受体之间的相似性表明，1 α，25-二羟维生素D3相互作用的同源机制可能在哺乳动物和鸟类肠道系统中起作用。
Specific cytoplasmic receptors for 1 alpha,25-dihydroxyvitamin D3 are shown to be present in human intestinal cytosol which are very similar to the analogous 1 alpha,25-dihydroxyvitamin D3 receptors present in chick intestinal cytosol. Both receptors are 3.5S proteins which aggregate under low ionic strength conditions. They have molecular weights of approximately 60,000 and Stokes' molecular radii of 33 A. The equilibrium dissociation constants for the receptors were both 2 X 10(-10) M at 4 C. The association rate constant for the human receptor was found to be 2.5 X 10(7) M-1 min-1 at 0 C, while a value of 0.5 X 10(7) M-1 min-1 was obtained for the chick receptor. The dissociation rate constants at 4 C were 6.4 X 10(-4) min-1 (human) and 3.6 X 10(-5) min-1 (chick). In addition, it was found that both receptors possessed reduced cysteine residues near the 1 alpha,25-dihydroxyvitamin D3-binding site which were critical for receptor-binding activity. The similarities between the human and the chick receptors suggests that homologous mechanisms for 1 alpha,25-dihydroxyvitamin D3 interactions may be at work in both mammalian and avian intestinal systems.