The determination of alpha-amylase with 2-chloro-4-nitrophenyl-beta-D-maltoheptaoside as substrate: comparison with other methods.

The determination of alpha-amylase with 2-chloro-4-nitrophenyl-beta-D-maltoheptaoside as substrate was evaluated. The molar lineic absorbance of the liberated product, 2-chloro-4-nitrophenol, depends on the concentration of the protein present in the test. The catalytic activity concentrations obtained with human native sera, urines and commercial test sera were compared with activity concentrations determined using substrates with the same carbohydrate chain length. The analytical agreement is acceptable for human sera and urines. The relative reaction rates measured with alpha-amylase of various origins and 7 different substrates are presented. The advantages of the new test are discussed.