Pyruvate is a central molecule in cellular metabolic pathways. Pyruvate can be converted to carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine and to ethanol. Abnormal levels of pyruvate have been linked to liver diseases and metabolic disorders. This colorimetric assay is based on pyruvate oxidase catalyzed oxidation of pyruvate, in which the formed hydrogen peroxide is catalyzed by peroxidase and reacts with 4-aminoantipyrine to form the product dye. The color intensity of the reaction product at 570nm is directly proportional to pyruvate concentration in the sample.