The presence of a 33-40 KDa gastrin binding protein on human and mouse colon cancer.
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.
Chicone
L
L
Department of Surgery, University of Texas Medical Branch, Galveston 77550.
Narayan
S
S
Townsend
C M
CM
Singh
P
P
D000818:Animals; D001345:Autoradiography; D002352:Carrier Proteins / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000378:metabolism*; D003432:Cross-Linking Reagents; D005755:Gastrins / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight
D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D005755:Gastrins