Human Salivary Glycosidases

Abstract

The activity of several glycosidases—neuraminidase, α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase, β-N-acetylglucosaminidase, α-mannosidase, β-glucuronidase, and α-L-fucosidase—was assayed in whole, parotid, and submaxillary–sublingual human saliva as well as in mixed cultures of oral microflora. All of these enzymes were present in whole saliva and, with the exception of α-mannosidase, were also present in mixed broth cultures of oral organisms from the same subjects. Only α-L-fucosidase and β-N-acetylglucosaminidase were found in sterile parotid and submaxillary–sublingual saliva. The latter had peaks of optimal pH activity that differed from those of the corresponding bacterial enzymes recovered from the same subject. Since salivary glycosidases can degrade salivary mucins they may be capable, under certain conditions, of attacking the surface layer of mucus in the stomach.