Watanabe Y, Tada H, Hidaka Y, Takano T, Amino N
Department of Laboratory Medicine, Osaka University Medical School, Suita, Japan.
Biochem Biophys Res Commun. 1998 Jul 9;248(1):110-4. doi: 10.1006/bbrc.1998.8928.
The effect of solubilization of porcine thyrotropin receptor (TSHR) on TSH binding and on the radio-receptor assay for anti-TSHR antibodies was examined. After TSHR solubilization with 1% dodecylpolyethy-leneglycoether, TSH binding affinity was increased, from Kd = 1.15 nM to 0.45 nM, and TSH binding capacity was slightly increased, from 0.15 nM to 0.19 nM. With a particulate membrane suspension from thyroid cells, blocking of TSH binding to the membrane suspension by anti-thyrotropin receptor antibody was observed only for thyroid stimulation blocking antibody (TSBAb), not for thyroid-stimulating antibody (TSAb). After the solubilization of TSHR, both TSBAb and TSAb blocked TSH-binding to the solubilized TSHR. We speculate that TSAb interacts with the TSHR in the native conformation without interfering with TSH binding, and that after the solubilization, any anti-TSHR antibody interferes with TSH-binding due to the conformational change in TSHR. With these particulate thyroid cell membrane preparations, we can detect only TSBAb by the radio-receptor assay.
研究了猪促甲状腺素受体（TSHR）增溶对促甲状腺素（TSH）结合以及抗TSHR抗体放射受体测定的影响。用1%十二烷基聚乙二醇醚使TSHR增溶后，TSH结合亲和力从Kd = 1.15 nM增加到0.45 nM，TSH结合容量从0.15 nM略有增加至0.19 nM。对于甲状腺细胞的颗粒膜悬液，仅观察到促甲状腺素受体抗体阻断甲状腺刺激阻断抗体（TSBAb）对TSH与膜悬液的结合，而甲状腺刺激抗体（TSAb）则无此作用。TSHR增溶后，TSBAb和TSAb均能阻断TSH与增溶TSHR的结合。我们推测，TSAb以天然构象与TSHR相互作用而不干扰TSH结合，增溶后，任何抗TSHR抗体由于TSHR构象改变而干扰TSH结合。使用这些甲状腺细胞颗粒膜制剂，通过放射受体测定我们只能检测到TSBAb。
