Purification of vasoactive intestinal peptide receptor from porcine liver by a newly designed one-step affinity chromatography |
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Authors: | A Couvineau T Voisin L Guijarro M Laburthe |
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Institution: | Unité de Recherche sur la Différenciation et la Neuroendocrinologie de Cellules Digestives, Institut National de la Santé et de la Recherche Médicale U178, Villejuif, France. |
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Abstract: | Vasoactive intestinal peptide (VIP) receptors were solubilized from porcine liver membrane using the zwitterionic detergent 3-(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid. The solubilized VIP receptor has been purified approximately 50,000-fold to apparent homogeneity by a one-step affinity chromatography using a newly designed VIP-polyacrylamide resin. The purified receptor bound 125I-VIP with a Kd of 22.3 +/- 0.7 nM and retained its peptide specificity toward VIP-related peptides. The specific activity of the purified receptor (16,400 pmol/mg of protein) was very close to the theoretical value (18,900 pmol/mg of protein) calculated assuming one binding site/protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of purified receptor revealed a single band with an Mr of 53,000 after either silver staining or radioiodination. Affinity labeling of the purified receptor with 125I-VIP using dithiobis(succinimidyl propionate) gave a single radioactive band, the labeling of which was completely inhibited by an excess of unlabeled VIP. In conclusion, an Mr 53,000 protein containing the VIP-binding site was purified to homogeneity by a one-step affinity chromatography using immobilized VIP. |
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