Selective Determination of L-Lysine with L-Lysine g-Dehydrogenase

Simple and sensitive spectrophotometric methods were developed for the selective determination of L-lysine. The assay methods were based on the spectrophotometric determination of NADHformed in the reaction catalyzed by L-lysine e-dehydrogenase (Procedure A) or the formazan produced on coupling of the dehydrogenase reaction with the reduction of a tetrazolium salt (Procedure B). Procedure B was applicable to the direct determination of L-lysine in rabbit serum.