| Abstract: | Peptide agonists covalently attached to tobacco mosaic virus exhibit such unusual properties as superpotency, superaffinity, enhanced resistance towards enzymic degradation, and prolonged action at the target cell. These properties can be exploited for the isolation by density-gradient centrifugation of membrane vesicles bearing specific receptors for the peptides and for radioactive and fluorescent labeling of cell-surface receptors. Our observations can be explained by cooperative–affinity phenomena caused by the deployment in space of the agonist molecules. |
