Sodium carbonate versus borate buffer for lactase quenching, laboratory work.

A laboratory exercise for undergraduate advanced students of enzymology and biocatalysis is presented. Since enzyme assays can be quenched or continuous, this experiment compares the performance of two quenching agents for lactase, in a continuous setup. Enzymatic activity of β-galactosidase (Aspergillus oryzae) was determined based on the release of 4-nitrophenol from 4-nitrophenyl β-D-galactopyranoside using a microplate reader.