Evidence for the presence of carbamino compounds in human saliva.

The bicarbonate concentrations of whole saliva and of protein-free filtrates of saliva were measured to test for the presence of carbamino compounds. If no acid-evolved CO2 were derived from the salivary proteins, then the two measured bicarbonate concentrations should be identical. Instead, the bicarbonate concentrations of the whole saliva samples were on the average 30% higher than that of their filtrates. The results are consistent with the conclusion that carbamino compounds account for the differences. Similar findings were obtained with samples of resting whole saliva and parotid saliva.