A spectrophotometric assay for meso-diaminopimelate decarboxylase and L-alpha-amino-epsilon-caprolactam hydrolase

A spectrophotometric assay for the activities of mesodiaminopimelate decarboxylase and L-alpha-amino-epsilon-caprolactam hydrolase is described. With the commercially available enzyme saccharopine dehydrogenase lysine formed either by decarboxylation of meso-diaminopimelate or by hydrolysis of L-alpha-amino-epsilon-caprolactam is converted to saccharopine with the concomitant oxidation of NADH, which is monitored by the decrease in absorbance at 340 nm. For meso-diaminopimelate decarboxylase this assay can be performed either as an endpoint determination, when working with crude extracts, or as a continuous spectrophotometric assay of partially purified enzyme preparations. The activity of L-alpha-amino-epsilon-caprolactam hydrolase can only be assayed by the endpoint method because of the great differences in the pH optima of the hydrolase and the saccharopine dehydrogenase.