human salivary 19-20 kDa glycoprotein; present mainly in submandibular-sublingual saliva; a potential enamel pellicle component; has been isolated and characterized; 13% carbohydrate content; molar ratio of Fuc:Man:Gal:GlcNAc:NeuAc = 3.4:2.6:2.9:4.0:0.4