Comparison of human pancreatic and parotid amylase activities on different substrates.

The specific activities of highly purified preparations of human parotid and pancreatic amylase on several different soluble and insoluble starches were compared. The ratio of parotid to pancreatic activity varied with the physical nature of the substrate. With all soluble starches, irrespective of source, parotid amylase exhibited a higher specific activity than did pancreatic amylase; the reverse was true for an insoluble chromogenic starch (Amylose Azure). The variation in enzyme-substrate interaction supports previous indications of configurational differences between the two amylases. The observed organ-specific characteristics according to organ of origin may have value in determining relative parotid and pancreatic amylase activities in body fluids under normal and pathological conditions, thereby helping to clarify their functional and clinical significance.