Glycolate oxidase（HAO1) belongs to the superfamily of the alpha hydroxy acid oxidases（HAO) enzymes. HAO1 catalyzes the FMN mediated oxidation of glycolate to glyoxylate and glyoxylate to oxalate with reduction of oxygen to hydrogen peroxide. HAO1 is most abundantly expressed in the liver and pancreas and is most active on twocarbon substrates such as glycolate. Lately， HAO1 has been identified as a key contributor to hyperoxaluria， a disorder in which large deposits of calcium oxalate form kidney stones.
