Assay of Amino Acid Racemases

d -Amino acids play important physiological roles in the mammalian body. Recent investigations revealed that, in mammals, d -amino acids are synthesized from their corresponding l -enantiomers via amino acid racemase. This article describes a method used to measure amino acid racemase activity by high-performance liquid chromatography (HPLC). The assay involves fluorogenic chiral derivatization of amino acids with a newly developed reagent, and enantioseparation of d - and l -amino acid derivatives by HPLC. The method is accurate and reliable, and can be automated using a programmable autosampling injector.