Complex sentence: Two enzymes with NAAG peptidase activity have since been cloned (glutamate carboxypeptidase II and glutamate carboxypeptidase III), which mediate the hydrolysis of NAAG to NAA and glutamate.
Split into simpler sentences: Two enzymes with NAAG peptidase activity have since been cloned (glutamate carboxypeptidase II and III). They mediate the hydrolysis of NAAG to NAA and glutamate.