Insulin and epidermal growth factor-urogastrone: affinity crosslinking to specific binding sites in rat liver membranes.

摘要: Abstract Both insulin and human epidermal growth factor-urogastrone (EGF/URO) can be covalently linked to specific rat liver membrane binding sites by glutaraldehyde coupling followed sodium borohydride reduction yield affinity-labeled constituents sufficiently stable for solubilization further analysis various techniques. Solubilization of membranes labeled with 125I-labeled yields a component chromatographic properties identical those soluble receptor characterized in previous studies. A second insulin-binding that is not revealed the affinity-labeling method has yet been reported also detected. Membranes similarly EGF/URO one major two minor ligand-specific (Triton X-100) components, as detected chromatography on Sepharose 6B. Further EGF/URO-labeled components affinity concanavalin A-Sepharose, disc gel electrophoresis, enzymatic digestion suggests glycoprotein subunit approximately 100,000 daltons possesses 20,000-dalton portion inaccessible proteolytic cleavage when anchored membrane. The labeling approach described should prove use study other polypeptide receptors that, like receptor, lose their ligand recognition property subsequent solubilization.