Wheat amylase inhibitor and its action on amylase activity.

Effect of wheat amylase inhibitor (Isoamylase test, Phadebus-Shionogi) on human pancreatic and salivary amylase activities were investigated. Column chromatographic investigations suggested the formation of an amylase-inhibitor complex, which easily dissociated into each component after electrophoresis and the amylase activity was fully recovered. Using the specific inhibitory effect of the inhibitor on salivary amylase activity, the ratio of activity of pancreatic to salivary amylase (P/S ratio) in serum was determined. P/S ratio of serum from patients with acute pancreatitis was more than 8.0 whereas that of serum from patients with mumps, with lung disease or postoperative hyperamylasemia associated with salivary-type hyperamylasemia was less than the normal value. However, hyperamylasemia due to macroamylasemia or renal failure could not be discriminated by this method, because the P/S ratio in these patients was the same as the normal value.