CHANGES OF "CARBOXYL-CO₂" AND OF AMMONIA PLUS-UREA NITROGEN IN SALIVA INCUBATED WITH GLUCOSE

¹ Harvard School of Dental Medicine, Boston, Mass.

1. The quantity of CO₂ liberated from human incubated saliva by the action of ninhydrin (designated as "carboxyl-CO₂") is increased approximately 100% when glucose is added.

2. The increase in "carboxyl-CO₂" provides evidence of a chemical nature for the liberation of additional amino acids in saliva maintained in contact with glucose at body temperature. This finding points toward free amino acids as the constituents of saliva incubated with glucose which enable saliva so treated to act as a substitute for tryptophane and to a lesser extent for other amino acids of a synthetic bacteriological medium.

3. The quantity of ammonia-plus-urea nitrogen increased from 200-400% when human saliva was incubated by itself for 24-192 hours. When glucose was added to the saliva the increases of ammonia-plus-urea nitrogen observed were only in the order of about 15%. In each circumstance the increase was almost entirely in the ammonia fraction. The results are interpreted as evidence that the presence of glucose in saliva favors the process of proteolysis over that of deamination.