Determination of total and pancreatic alpha-amylase in human serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate.

A reagent and assay conditions for the determination of the catalytic concentration of alpha-amylase (E.C. 3.2.1.1) in serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate are described. The selected reaction mixture contains 50 mmol/l 2-(N-morpholino)ethanesulfonic acid buffer at pH 6.1 (37 degrees C), 300 mmol/l sodium chloride, 5 mmol/l calcium chloride and 450 mmol/l potassium thiocyanate. The described method is suitable for the measurement of total as well as pancreatic alpha-amylase by including antibodies against the salivary isoenzyme. The method shows the absence of a lag phase period, is sensitive and precise, has a large analytical range and is free from interference by hemoglobin, bilirubin and triglycerides. Comparative studies showed good correlation with other well established methods.