On electrophoresis, parotid saliva always exhibits a basic pattern of 6 isoamylases. Additional faster migrating isoamylases occur in varying numbers. These "fast isoamylases" are generated, at least in part, by deamidation. Compared with juvenile and adult controls, a significantly greater number of "fast isoamylases" was found in the parotid saliva of children with cystic fibrosis and their healthy heterozygous parents. A shift in the equilibrium between amidation and deamidation is discussed in terms of its possible connection with the metabolic defect responsible for cystic fibrosis.

An increased number of 'fast isoamylases' is found in the parotid saliva of children with cystic fibrosis and their heterozygous parents who are clinically healthy. 'Fast isoamylases' are generated, at least in part, from the 6 isoamylases of the basic pattern by deamidation of asparagine and glutamine residues. This basic pattern is present in the parotid saliva of all subjects we have tested so far. A shift in the equilibrium between amidation and deamidation processes is discussed in terms of its possible significance for the pathogenesis of cystic fibrosis and for ageing.

Human parotid saliva is characterized by a basic pattern of 6 isoamylases; during ageing, it contains additional isoamylases which migrate faster towards the anode. An increasing number of 'fast isoamylases' are also found in saliva from mucoviscidosis patients. Their possible symptomatological significance for the pathogenesis of mucoviscidosis which is as yet not solved is being discussed.