The histochemistry of asparagine-linked oligosaccharides of glycoproteins in mammalian and avian tissues as studied by digestion with almond glycopeptidase.

In a series of mammalian and avian tissues, asparagine-linked oligosaccharides of glycoproteins have been localized histochemically by means of combined periodic acid-Schiff (PAS) and almond glycopeptidase digestion procedures. According to the present results, the particular saccharide residues were found to be localized primarily in glycoproteins of connective and muscular tissue elements but were hardly visualizable or absent in glycoproteins of epithelial tissue elements. In view of the substrate specificity of almond glycopeptidase and the known staining selectivity of the PAS reaction, the majority of connective and muscular tissue elements are thought to be the main sites where plasma types of glycoproteins are involved.