Simpson R U, DeLuca H F
Proc Natl Acad Sci U S A. 1980 Oct;77(10):5822-6. doi: 10.1073/pnas.77.10.5822.
Isolated rat epidermis possesses a cytosolic 3.5 S receptor-like protein for 1,25-dihydroxyvitamin D3. This 3.5S binder has a high affinity (Kd = 1.4 X 10(-10) M) for 1,25-dihydroxyvitamin D3 and is present in low concentrations (31 fmol of binding sites per mg of cytosol protein). Analog competition for receptor binding revealed the following potency order: 1,25-dihydroxyvitamin D3 > 25-hydroxyvitamin D3 > 1 alpha-hydroxyvitamin D3 > 24 (R),25-dihydroxyvitamin D3 > vitamin D3. The receptor has a molecular weight of 60,000, has affinity for DNA-cellulose, and aggregates in the presence of low potassium concentrations. The 1,25-dihydroxyvitamin D3 binder is stabilized by sodium molybdate (10 mM). Addition of phenylmethylsulfonyl fluoride (3 mM) was found to yield more reproducible receptor preparations. The presence of a 1,25-dihydroxyvitamin D3 binding macromolecule with properties similar to those of the bone and intestinal receptor suggests that skin is an additional target organ for this hormone.
分离出的大鼠表皮含有一种胞质溶胶中与1,25 - 二羟维生素D3结合的3.5S受体样蛋白。这种3.5S结合蛋白对1,25 - 二羟维生素D3具有高亲和力(解离常数Kd = 1.4×10⁻¹⁰ M),且以低浓度存在(每毫克胞质溶胶蛋白中有31飞摩尔结合位点)。受体结合的类似物竞争显示出以下效力顺序:1,25 - 二羟维生素D3>25 - 羟维生素D3>1α - 羟维生素D3>24(R),25 - 二羟维生素D3>维生素D3。该受体分子量为60,000,对DNA - 纤维素有亲和力,在低钾浓度下会聚集。1,25 - 二羟维生素D3结合蛋白可被钼酸钠(10 mM)稳定。发现添加苯甲基磺酰氟(3 mM)可得到更具重复性的受体制剂。存在一种与骨骼和肠道受体性质相似的1,25 - 二羟维生素D3结合大分子,这表明皮肤是这种激素的另一个靶器官。