Enzymatic determination of several D-amino acids using luminol-mediated chemiluminescence

A method for the quantitative determination of several D-amino acids in the range of 0.05-1 nmol per assay (0.25-5 microM) is described. It is insensitive to the presence of excesses of the respective L-amino acids. The assay system employs D-amino-acid oxidase (hog kidney), peroxidase (horse radish) and luminol; the total photon output elicited by the oxidation of the D-amino acids is determined. The different reactivity of individual D-amino acids with D-amino-acid oxidase limits the applicability of the assay. Indications for the usefulness of immobilized enzymes in D-amino-acid analysers are also given.