Visualization of lactotransferrin brush-border receptors by ligand-blotting.

摘要: The uptake of iron (III) mediated by lactotransferrin to human biopsies from upper intestine has suggested the presence specific receptors for at brush border (Cox, T., Mazurier, J., Spik, G., Montreuil, J. and Peters, T.J. (1979) Biochim. Biophys. Acta 588, 120-128). In present data, using 125I-radiolabeled transferrins, we have demonstrated that a preparation microvillous membrane vesicles, rabbit jejunal brush-border specifically binds lactotransferrin. This binding is specific, saturable calcium dependent. Scatchard plots analysis indicates 1.5 X 10(13) sites per mg proteins with an equilibrium constant 1.2 10(6) M-1. Sodium dodecyl sulfate solubilization allows receptor retain its activity. Moreover, ligand blotting detergent solubilized on nitrocellulose sheet after incubation 125I-labeled lactotransferrin, shown protein about 100 kDa. same experimental conditions, vesicles do not bind serotransferrin indicating absence border.