Amylase test involves use of a chromogenic substrate Gal G, – a CNP (2-chloro-4-nitrophenyl linked with galactosyl maltoside). The direct action of amylase with this substrate results in the release of more than 90% of 2-chloro-4-nitrophenol, which can be monitored by kinetic assay at 405 nm. The increase in absorbance is directly proportional to the amylase activity in the sample.