Amylase inhibitor from wheat: its action and clinical application.

The electrophoretic and column chromatographic characteristics of an amylase inhibitor of wheat origin were investigated. Further, the clinical usefulness of this inhibitor for determining the ratio of pancreatic to salivary isoamylase activity in serum was evaluated. Amylase inhibitor inhibits the action of salivary alpha-amylase by making an amylase-inhibitor complex, which is easily separated into its individual component during electrophoresis with full recovery of amylase activity. Using the specific inhibitory effect of this inhibitor on salivary alpha-amylase activity, the ratio of pancreatic to salivary isoamylase activity (P/S) in serum was determined. There was a good correlation in P/S ratio in serum between the results obtained with the inhibitor method and those with electrophoretic method. The P/S ratio in sera from patients with acute pancreatitis was over 8.0, whereas that in sera from patients with salivary-type hyperamylasemia such as mumps, pulmonary diseases and following surgery was less than 0.1. However, hyperamylasemia due to macroamylase or renal failure could not be identified by the inhibitor method.