Identification of bacterial glycosidases in rat cecal contents.

Cecal contents of conventional and germfree rats were examined for glycosidases which may have a role in degrading glycoprotein oligosaccharides. Utilizing p-nitrophenylglycosides as substrates, we identified glycosidases in bacteria-free supernatants from cecal contents which act on beta-linkages. These cecal glycosidases appear to be of bacterial origin since: (1) direct comparisons of the enzymes in similar contents from germfree rats showed negligible activities; (2) most of the glycosidase levels in bacterial extracts were at least as high as those of soluble supernatants; and (3) disk gel electrophoresis of contents and bacterial extracts revealed in both preparations a beta-N-acetylglucosaminidase band with similar Rfs. Also, the blood group B antigenicity of germfree cecal glycoproteins was greatly decreased by conventional cecal contents. These findings indicate that beta-galactosidase and beta-N-acetylgalactosaminidase in cecal contents are bacterial in origin, and they may have a role in the bacterial catabolism of intestinal glycoproteins.