Hashizume K, Suzuki S, Ichikawa K, Takeda T
Department of Geriatrics, Endocrinology and Metabolism, Shinshu University School of Medicine, Matsumoto, Japan.
Biochem Biophys Res Commun. 1991 Feb 14;174(3):1084-9. doi: 10.1016/0006-291x(91)91531-g.
The NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine(T3)-binding protein(CTBP) was purified from rat kidney using Mono Q-Sepharose, Red sepharose and T3 affinity chromatography. CTBP which was partially purified by Red Sepharose column chromatography was adsorbed to T3 affinity column in the presence of 50 uM NADPH. The CTBP was eluted from the gel with the buffer which did not contain NADPH. One molecule of the purified CTBP(58 kDa) bound one molecule of T3 with 2.44 x 10(9) M-1 of affinity constant. The purified CTBP was activated not only by NADPH but also by NADP in the presence of dithiothreitol. The NADPH-activated form did not transfer T3 to nuclei, whereas NADP transformed the NADPH-activated CTBP to active form which was able to transfer T3 to nuclei. These results suggested that CTBP-dependent transport of T3 to nucleus is controlled by NADPH and NADP.
利用单Q-琼脂糖凝胶、红色琼脂糖凝胶和三碘甲状腺原氨酸（T3）亲和层析法从大鼠肾脏中纯化出依赖烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的胞质3,5,3'-三碘-L-甲状腺原氨酸（T3）结合蛋白（CTBP）。经红色琼脂糖凝胶柱层析部分纯化的CTBP在50 μM NADPH存在的情况下吸附到T3亲和柱上。CTBP用不含NADPH的缓冲液从凝胶上洗脱下来。纯化后的CTBP（58 kDa）的一个分子以2.44×10⁹ M⁻¹的亲和常数结合一个分子的T3。纯化后的CTBP不仅在二硫苏糖醇存在的情况下被NADPH激活，还被烟酰胺腺嘌呤二核苷酸磷酸（NADP）激活。NADPH激活的形式不能将T3转运到细胞核，而NADP将NADPH激活的CTBP转化为能够将T3转运到细胞核的活性形式。这些结果表明，CTBP依赖的T3向细胞核的转运受NADPH和NADP的控制。
