Transglutaminase 2 (TG2, "tissue" TG) belongs to the family of the Transglutaminase (TG) enzymes, which catalyse post-translational modifications of proteins, such as the cross linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate with the formation of an N-gamma-(epsilon-L-glutamyl)-L-lysine [GGEL] cross link (isopeptidic bond) and the concomitant release of ammonia.