The covalent modification of TG2 substrates such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alpha-ketoglutarate dehydrogenase, phosphoglycerate dehydrogenase, and fatty acid synthase [95], which are involved in energy metabolism, could account for the role of TG2 in metabolic diseases. This evidence concerns the gene GAPDH and Other metabolic disease.