GAPDH (glyceraldehyde-3-phosphate dehydrogenase) is an intracellular homotetramerizing enzyme, which catalyzes oxidation of glyceraldehyde-3-phosphate into 1,3-bisphosphoglycerate during glycolysis, and has also functions in DNA replication, gene expression, and microtubule bundling. As it binds to many proteins, its functions are very broad. GAPDH plays also roles in cancer progression, apoptosis, Huntington disease and Alzheimer´s disease.