L-Amino Acid Oxidase is an oligomeric glycoprotein composed of unequal amounts of two different approximately 70 kDa subunits. Three electrophoretically different isozymes occur as different combinations of the two subunits. there are approximately two moles of FAD per mole of holo-enzyme. L-amino acid oxidase catalyzes the oxidative deamination of a number of L-amino acids. The enzyme is absolutely specific for L-isomers. The Aladdin product is prepared according to Wellner and Meister, JBC, 235, 2013, (1960) to the point just prior to crystallization.