Platelet-derived growth factor receptors form a high affinity state in membrane preparations. Kinetics and affinity cross-linking studies.

摘要: The specific binding of 125I-PDGF (platelet-derived growth factor) to intact fibroblasts becomes relatively nondissociable during incubation at 37 degrees C. To characterize the interaction PDGF with its receptors under conditions in which there is no receptor internalization, we have studied membrane preparations derived from mouse 3T3 cells and rat liver. sites had affinity specificity characteristics expected receptors. At C (but not 4 C) membranes gradually became as assessed by either dilution or addition excess unlabeled PDGF. This tight was due a covalent since polyanionic compound suramin readily dissociated specifically bound 125I-PDGF. property used expose liver were occupied endogenous Affinity cross-linking studies demonstrated that formation state associated 160,000-dalton protein 110,000-dalton species. cross-linked could be adsorbed wheat germ agglutinin anion exchange resins. isoelectric point both species determined two-dimensional gel electrophoresis approximately 4.7. These data demonstrate preparations, binds an anionic glycoprotein likely receptor. A high binding, formed rapidly C, can suramin.