Johnson W A, Nathanson N M, Horita A
Proc Natl Acad Sci U S A. 1984 Jul;81(13):4227-31. doi: 10.1073/pnas.81.13.4227.
The thyrotropin-releasing hormone receptor from rat brain was solubilized in a stable unbound form. The natural glycoside digitonin was the only detergent of a variety tested capable of solubilizing the active receptor. The digitonin-solubilized receptor exhibited binding kinetics for 3-[3H]methylhistidine thyrotropin-releasing hormone virtually identical to membrane preparations and responded with a similar order of potency to a series of thyrotropin-releasing hormone analogues that inhibit binding of the labeled ligand. Gel filtration analysis and sucrose density gradient centrifugation indicated a Stokes radius of 5.2 nm, a sedimentation coefficient of 11.2 s, and a corresponding calculated molecular weight of 244,000 for the detergent-receptor complex. The soluble receptor shows a gradual loss of binding activity over 48 to 72 hr when kept at 4 degrees C. However, the preparation may be frozen at -20 degrees C with no significant loss of activity.
大鼠脑促甲状腺激素释放激素受体以稳定的未结合形式溶解。在所测试的多种去污剂中，天然糖苷洋地黄皂苷是唯一能够溶解活性受体的去污剂。洋地黄皂苷溶解的受体对3-[3H]甲基组氨酸促甲状腺激素释放激素的结合动力学与膜制剂几乎相同，并且对一系列抑制标记配体结合的促甲状腺激素释放激素类似物的反应效力顺序相似。凝胶过滤分析和蔗糖密度梯度离心表明，去污剂-受体复合物的斯托克斯半径为5.2纳米，沉降系数为11.2秒，相应计算出的分子量为244,000。当在4℃保存时，可溶性受体在48至72小时内结合活性逐渐丧失。然而，该制剂可在-20℃冷冻，活性无明显损失。
