Determination of L-Amino Acids and L-Amino Acid Oxidase Activity Using Luminol Chemiluminescence

Abstract

Abstract A quantitative enzymatic method has been developed for analysis of most of the naturally occurring L-amino acids as well as the enzyme L-amino acid oxidase. The method is based on the reaction of L-amino acid oxidase with L-amino acids to generate hydrogen peroxide. The peroxide is then determined by reacting it with excess luminol and ferricyanide and measuring the resulting chemiluminescence. The lower limit of detection for any particular amino acid is related to the specific activity of the enzyme for that substrate. Concentrations as low as 5.0 × 10−8 M are measurable for some amino acids. Using L-phenylalanine as a substrate, enzyme activity can be measured in the range of 0.012 to 0.21 U. of enzyme.