The isolation from human parotid saliva and partial characterization of the protein core of a major parotid glycoprotein

A protein was isolated from stimulated human parotid saliva which appears to be the core protein of a major parotid glycoprotein. This molecule was isolated by sequential chromatography on DEAE-cellulose, Sephadex G-200, and Sephadex G-25 from the parotid saliva of a single individual. The core protein had an amino acid composition similar to that of the protein moiety of the parotid glycoprotein and cross reacted immunologically with this glycoprotein. Immunoelectrophoretic analyses of both stimulated and unstimulated parotid saliva revealed that the core protein was not detectable in the unstimulated secretion. These data indicated that gustatory stimulation resulted in the secretion of incompletely synthesized molecules.