用[125I]三碘甲状腺原氨酸对大鼠肝脏细胞核甲状腺激素受体进行光亲和标记。

Photoaffinity labelling of the rat liver nuclear thyroid hormone receptor with [125I]triiodothyronine.

作者信息

David-Inouye Y, Somack R, Nordeen S K, Apriletti J W, Baxter J D, Eberhardt N L

出版信息

Endocrinology. 1982 Nov;111(5):1758-60. doi: 10.1210/endo-111-5-1758.

Abstract

[125I]Triiodothyronine (T3) was used as a photoreactive probe for the thyroid hormone nuclear receptor in photoaffinity labelling experiments. Autoradiograms of photolysis products electrophoresed on either one or two-dimensional gels showed that [125I]T3 covalently, but nonspecifically, labelled many proteins in the partially purified receptor preparations used. However, one of these proteins with an estimated molecular weight of 47,000 and an isoelectric point of approximately 6.2 +/- 0.5 pH units appears to be the thyroid hormone receptor, since, in contrast to the other proteins, its photoinduced labelling was blocked by concentrations of T3 and thyroxine (T4) similar to those that inhibit binding of [125I]T3 by the receptor in equilibrium binding assays. In addition, the isoelectric point of the photolabelled protein agrees with that determined in separate equilibrium isoelectric focusing studies. These results indicate that [125I]T3 can serve as a photoreactive probe for the thyroid hormone nuclear receptor, and they suggest that this receptor is a single polypeptide chain of molecular weight 47,000 with an isoelectric point of 6.2 +/- 0.5 pH units.

摘要

在光亲和标记实验中，[125I]三碘甲状腺原氨酸（T3）被用作甲状腺激素核受体的光反应性探针。在一维或二维凝胶上电泳的光解产物的放射自显影片显示，[125I]T3共价但非特异性地标记了所用部分纯化受体制剂中的许多蛋白质。然而，其中一种估计分子量为47,000且等电点约为6.2±0.5个pH单位的蛋白质似乎是甲状腺激素受体，因为与其他蛋白质相比，其光诱导标记被与平衡结合试验中抑制受体结合[125I]T3的浓度相似的T3和甲状腺素（T4）浓度所阻断。此外，光标记蛋白质的等电点与单独的平衡等电聚焦研究中确定的等电点一致。这些结果表明，[125I]T3可作为甲状腺激素核受体的光反应性探针，并且表明该受体是分子量为47,000且等电点为6.2±0.5个pH单位的单条多肽链。