Molecular characteristics and peptide specificity of bradykinin binding sites in intact neuroblastoma-glioma cells in culture (NG 108-15).

Here we report that the mouse neuroblastoma-glioma hybrid cell line NG108-15 possess high-affinity binding sites for the nonapeptide bradykinin, as revealed by competitive displacement of 125I-8Tyr bradykinin by various bradykinin analogs. These binding sites were further characterized by covalent cross-linking of 125I-8Tyr bradykinin to intact NG108-15 grown as a monolayer, using dithiobis-succinimidylpropionate (DTSP) as a cross-linking reagent. Sodium dodecyl sulfate (SDS) electrophoresis after solubilization of the cross-linked cells, demonstrated the preferential and specific labeling of two polypeptides with apparent molecular weights of Mr = 36,000 and Mr = 47,000. A third polypeptide of Mr = 69,000 was labeled less intensely.