2-Chloro-4-nitrophenyl-4-O-b-D-

to assay amylase activity, using nitrophenylated oligo-saccharides as substrate; however, the hydrolysis steps in these methods are complex. Methods: We developed a new continuously monitor-ing assay for amylase activity in biological fluids, using 2-chloro-4-nitrophenyl-4-O-b-D-galactopyranosylmalto-side (GalG2CNP) as the substrate; this assay was used with anti-human salivary amylase monoclonal antibod-ies for specific determination of the pancreatic isoen-zyme. Amylase converted GalG2CNP into b-D-galacto-pyranosylmaltose and 2-chloro-4-nitrophenol, which was measured at 405 nm. Results: GalG2CNP was cleaved between 2-chloro-4-nitrophenol and b-D-galactopyranosylmaltose and did not undergo transfer reactions. The within-assay CV