Poland A, Glover E, Ebetino H, Kende A
Food Chem Toxicol. 1986 Jun-Jul;24(6-7):781-7. doi: 10.1016/0278-6915(86)90186-9.
A series of halodibenzo-p-dioxins bearing the arylazide photolabile functional group were synthesized and tested as photoaffinity labels for the Ah receptor. 2-Azido-3-iodo-7,8-dibromodibenzo-p-dioxin (KD = 0.76 X 10(-9) M) was selected for radiosynthesis. Analysis of the 125I-photoaffinity-labelled proteins in mouse-liver cytosol by denaturing gel electrophoresis revealed two peptides which had apparent molecular masses of 95,000 and 70,000 daltons respectively, were labelled in an approximately 1:1 ratio and were selectively labelled at low concentrations of the photoaffinity ligand (0.05 KD = 0.04 X 10(-9) M). In addition, their labelling was inhibited by co-incubation with an excess of unlabelled ligand. On chromatographic separation under non-denaturing conditions, these two peptides co-migrated. These studies suggest that the Ah receptor in mouse liver cytosol is a heterodimer composed of two non-covalently bound peptides (95 K and 70 K) which each have a ligand binding site.
合成了一系列带有芳基叠氮光不稳定官能团的卤代二苯并 - 对 - 二噁英，并将其作为芳烃（Ah）受体的光亲和标记物进行测试。选择2 - 叠氮基 - 3 - 碘 - 7,8 - 二溴二苯并 - 对 - 二噁英（KD = 0.76×10⁻⁹ M）进行放射性合成。通过变性凝胶电泳分析小鼠肝脏胞质溶胶中¹²⁵I光亲和标记的蛋白质，发现两条肽段，其表观分子量分别为95,000和70,000道尔顿，以大约1:1的比例被标记，并且在低浓度光亲和配体（0.05 KD = 0.04×10⁻⁹ M）下被选择性标记。此外，与过量未标记配体共同孵育可抑制它们的标记。在非变性条件下进行色谱分离时，这两条肽段共同迁移。这些研究表明，小鼠肝脏胞质溶胶中的Ah受体是由两个非共价结合的肽段（95K和70K）组成的异二聚体，每个肽段都有一个配体结合位点。
