Measurement of Glutamate Carboxypeptidase II (NAALADase) Enzyme Activity by the Hydrolysis of [3H]‐N‐Acetylaspartylglutamate (NAAG)

Abstract The peptide N ‐Acetylaspartylglutamate (NAAG) is hydrolyzed by N ‐Acetylated‐alpha‐linked‐acidic dipeptidase (NAALADase, glutamate carboxypeptidase II) into N ‐Acetylated aspartate (NAA) and glutamate. Hydrolysis can be measured as described in this unit by employing radiolabeled NAAG (NAA‐[ 3 H]glu) as the substrate. The occurrence of NAALADase activity in a wide range of tissues has implications for a variety of physiological purposes. The assay described here is useful for the analysis of NAALADase activity and its inhibition in brain synaptosomal preparations, tissue homogenates and tissue culture cell pellets.