An alpha-amylase inhibitor was prepared from wheat seeds of Triticum aestivum species. Purification of this protein was carried via steps of aqueous extraction, alcohol fractionation, ion-exchange chromatography on QAE-Sephadex A 50 and DEAE cellulose (DE 52). This inhibitor showed molecular weights of 23442 daltons and 10965 daltons of subunits on SDS-PAGE. The specific activity of purified inhibitor on salivary type-amylase was 781.8 units/mg protein. There was a good correlation (r = 0.975) of serum % P-type amylase obtained from home-made and commercial inhibitors. Isoamylases were determined in 111 sera, including 30 healthy subjects, and 81 patients. Reference intervals were 78-210 U/L and 28-68 % for total amylase activity and % P-type amylase

respectively. Hyperamylasemia (total amylase exceeded referent value) was found in 30 out of 81 patients (37 %). Particularly, 92 % of acute pancreatitis (22/24) had hyperamylasemia with increasing of % P-type amylase (higher than 75 %). In group of nonpancreatic diseases that often present clinical pictures semilar to pancreatic disease, hyperamylasemia (total amylase exceeded referent value) was found only 4 % of the patients. In group of nongastrointestinal diseases that often present hyperamylasemia (total amylase exceeded referent value), there were 27 % of patients demonstrated hyperamylasemia. Whenever hyperamylasemia was judging with % P-type amylase more than 75 %, there was only 1 patient in group of nonpancreatic diseases that often present clinical pictures semilar to pancreatic disease and only 1 patient in group of nongastrointestinal diseases that often present hyperamylasemia. In conclusion, it should be stated that inhibition method by home-made inhibitor offers the simple, rapid and economical isoamylases test. Hyperamylasemia with % P-type amylase higher than 75 % is a superior index for diagnosis of acute pancreatitis.