Development of a direct assay for α-amylase

Abstract

We describe a direct colorimetric assay for α-amylase, with 2-chloro-4-nitrophenyl-α-maltotrioside as substrate. Both human pancreatic and salivary amylase split this substrate without the use of helper enzymes, yielding free 2-chloro-4-nitrophenol, which is monitored at 405 nm. The performance of this reagent compares well with that of Pantrak Amylase (Behring Diagnostics) for both serum and urine samples. The reagent is very stable in dry powder form and is stable for one month at 2 to 8°C after reconstitution. Because of the rapid color development and linear kinetics (< 30 s), the assay is easily automated. Results can be obtained in < 5 min.