Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is an enzyme of about 37kDa that catalyzes the sixth step of glycolysis and thus serves to break down glucose for energy and carbon molecules [PMID: 17072346]. GAPDH comprises a polypeptide chain of 335 amino acids. Structural studies identified two regions, namely the glyceraldehyde-3-phosphate catalytic site and the NAD+ binding site, a primary structure known as the Rossmann fold, which is also required for the activity of other dehydrogenases. Many of these roles are dependent on the ability of GAPDH to bind different macromolecules in the cell.