Identification of a 50,000 Mr protein from rabbit brush border membranes that binds Clostridium perfringens enterotoxin

A protein that binds Clostridium perfringens enterotoxin was extracted with NP-40 from rabbit intestinal brush border membranes. This protein was partially purified by affinity chromatography on enterotoxin-coupled CNBr-activated Sepharose 4B. The molecular weight of this protein was approximately 50,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Affinity-purified samples containing this protein specifically inhibited biological activity of the enterotoxin on Vero (African green monkey kidney) cells. These studies suggest that this protein may be involved in the binding of the enterotoxin to rabbit intestinal epithelial cells.