Characterization and intermethod relationships of materials containing purified human pancreatic and salivary amylase

We describe the preparation and characterization of materials containing human pancreatic and salivary alpha-amylase (EC 3.2.1.1) and examine their relationship to endogenous amylase in human serum. Amylase was purified from human pancreas and saliva by solvent- and salt-fractionation and column chromatography to specific activities of 63 and 279 kU/g, respectively. Four liquid pools, differing only in activity, were prepared from each source of amylase, each in a matrix containing, per liter: 30 g of human albumin, 50 mmol of sodium chloride, 1 mmol of calcium chloride, and 50 mmol of Tris hydrochloride buffer, pH 7.4. Characterization of the pools showed that the amylase activity in the materials was stable for at least six months at 25 degrees C; among-vial variability of amylase activity was less than or equal to 0.5% (2 CV); and the pools were free from eight possible contaminating enzymes. Plots of salivary vs pancreatic amylase activity measure in our materials with eight commercially available methods showed least-squares slopes ranging from 0.51 to 1.0. The intermethod "commutability" of the materials (i.e., how closely they mimic endogenous serum amylase) was examined in relationship to approximately 100 human sera.