Characterization of cholecystokinin receptors on rat pancreatic membranes.
Characterization of cholecystokinin receptors on rat pancreatic membranes.
复制标题
大鼠胰膜上胆囊收缩素受体的表征。
DOI：
10.1210/endo-109-5-1746
复制
发表时间：
1981
期刊：
影响因子：
4.8
通讯作者：
J. Williams
中科院分区：
文献类型：
--
作者：
R. Steigerwalt;J. Williams
用[125 I]Bolton-Hunter试剂（[125 I]BH）与胆囊收缩素（CCK）33偶联，制备了具有生物活性的放射性碘标记CCK 33，研究了CCK与大鼠胰腺膜受体的结合。在pH7.4和24 ℃下，25 pM [125 I]BHCCK与胰腺受体的结合在120 min后达到最大，加入1 μM未标记配体后可逆。[125 I]BHCCK结合也在各种组织的膜制备物中进行了测试，但仅在胰腺和大脑皮层中发现了特异性结合。胰腺结合数据的Scatchard分析揭示了一类CCK结合位点，Kd为1.35 nM，结合能力为204 fmol/mg蛋白。最佳[125 I]BH-CCK结合需要5 IDM Mg 2+和1 mM EGTA;相反，单价阳离子（Na+或K+）抑制结合。[125 I]-BH-CCK结合显示出最适酸性pH值为5.5;在此pH值下结合的增加主要是由于容量增加（至399 fmol/mg p.
In the present study cholecystokinin (CCK) binding to its receptors on rat pancreatic membranes was characterized by the use of biologically active radioiodinated CCK33prepared by conjugation of [125I]Bolton-Hunter reagent ([125I]BH) to CCK33. At pH 7.4 and 24 C, the binding of 25 pM [125I]BHCCK to pancreatic receptors was maximal after 120 min and reversible upon the addition of 1 μM unlabeled ligand. [125I]BHCCK binding was also tested in membrane preparations from a variety of tissues, but specific binding was found only in the pancreas and cerebral cortex. Scatchard analysis of the pancreas binding data revealed a single class of CCK-binding sites, with a Kd of 1.35 nM and a binding capacity of 204 fmol/mg protein. Optimal [125I]BH-CCK binding required 5 IDM Mg2+ and 1 mM EGTA; in contrast, monovalent cations (either Na+ or K+) inhibited binding. [125I]-BH-CCK binding exhibit d an acid pH optimum of 5.5; the increase in binding at this pH was due primarily to an increase in capacity (to 399 fmol/mg pr...