The alpha-amylases hydrolyze alpha-1,4-glucoside bonds in polymers of glucose units. Kamaryt and Laxova  found 2 amylase isoenzymes in serum, one produced by the salivary gland and the second by the pancreas. In 11 of 120 children, a duplication of pancreatic enzyme band was found on starch gel electrophoresis and in each case 1 parent also showed the duplication. In the mouse the salivary and pancreatic amylases are determined by genes at closely linked loci.

The separate loci in the human were designated AMY1 (salivary) and AMY2 (pancreatic). Polymorphism of both the salivary and the pancreatic serum amylases has been demonstrated in man. Ward et al. (1971) studied amylase in saliva and identified electrophoretic variants.