Age-dependent distribution of isoamylases in human parotid saliva.

The number of isoamylases present in parotid saliva from 53 healthy men and women of different ages was determined. A basic pattern of 6 isoamylases was evident in all samples. With increasing age, an increasing number of additional isoenzymes was observed which migrated faster towards the anode. These 'fast isoamylases' are derived from the basic isoenzymes by deamidation. The significance of deamidation of proteins as age increases as well as the increasing number of 'fast isoamylases' in saliva from mucoviscidosis patients are discussed.