Chicone L, Narayan S, Townsend C M, Singh P
Department of Surgery, University of Texas Medical Branch, Galveston 77550.
Biochem Biophys Res Commun. 1989 Oct 16;164(1):512-9. doi: 10.1016/0006-291x(89)91749-x.
Human and mouse colon cancers have specific binding sites for gastrin and demonstrate a trophic response to gastrin. In the present study we used radiolabeled gastrin (2-17), to determine the molecular weight of gastrin binding proteins (receptors) on mouse and human colon cancers, by cross-linking methods. Crude membrane aliquots prepared from the tumors were radiolabeled with [125I]gastrin (2-17) +/- 1000 fold excess of unlabeled gastrin and cross-linked with 1 mM disuccinimidyl suberate. The cross-linked radiolabeled binding protein complexes were solubilized and subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis. The autoradiographs of the gels demonstrated the presence of a predominant band of approximately 33-40 KDa gastrin binding protein, that was specific for gastrin analogs. Our present findings thus indicate that specific gastrin binding proteins/gastrin receptors on colon cancers are primarily present as one band with a molecular mass of approximately 33-40 KDa and are specific for gastrin-like peptides.
人类和小鼠结肠癌具有胃泌素的特异性结合位点，并对胃泌素表现出营养反应。在本研究中，我们使用放射性标记的胃泌素（2-17），通过交联方法来确定小鼠和人类结肠癌上胃泌素结合蛋白（受体）的分子量。从肿瘤制备的粗制膜等分试样用[125I]胃泌素（2-17）进行放射性标记，同时加入或不加入1000倍过量的未标记胃泌素，并用1 mM辛二酸二琥珀酰亚胺酯进行交联。将交联的放射性标记结合蛋白复合物溶解，并进行十二烷基硫酸钠聚丙烯酰胺凝胶电泳。凝胶的放射自显影片显示存在一条约33 - 40 kDa的主要胃泌素结合蛋白条带，该条带对胃泌素类似物具有特异性。因此，我们目前的研究结果表明，结肠癌上的特异性胃泌素结合蛋白/胃泌素受体主要以一条分子量约为33 - 40 kDa的条带形式存在，并且对胃泌素样肽具有特异性。
