The free amino acid composition of human saliva

The quantitative free amino acid composition of whole saliva and parotid and submaxillary secretions collected on 3 or 4 separate days was determined in three individuals. Free amino acids were determined semiquantitatively in the whole saliva of six individuals collected on 10 separate days over a period of 3 weeks. Eighteen free amino acids were found in whole saliva, with the concentration of some amino acids varying considerably in individual salivas. Six amino acids were found consistently and three inconsistently and in very small quantities in parotid secretions. Twelve amino acids were found regularly and two irregularly in submaxillary secretions. A comparison of whole saliva and submaxillary secretion from an individual indicates that approximately one-half of the free amino acids in whole saliva are submaxillary in origin. The ammonia nitrogen, amino nitrogen and total nitrogen were determined in the whole saliva of six individuals.