Synonym(s): Protein-glutamine gamma-glutamyltransferase, Fibrinoligase, TGase <p>Protein-glutamine gamma-glutamyltransferases (<db_xref db="EC" dbkey="2.3.2.13"/>) (TGase) are calcium-dependent enzymes that catalyse the cross-linking of proteins by promoting the formation of isopeptide bonds between the gamma-carboxyl group of a glutamine in one polypeptide chain and the epsilon-amino group of a lysine in a second polypeptide chain. TGases also catalyse the conjugation of polyamines toproteins [<cite idref="PUB00001513"/>, <cite idref="PUB00002570"/>].</p><p>Transglutaminases are widely distributed in various organs, tissues andbody fluids. The best known transglutaminase is blood coagulation factor XIII,a plasma tetrameric protein composed of two catalytic A subunits and twonon-catalytic B subunits. Factor XIII is responsible for cross-linking fibrin chains, thus stabilising the fibrin clot.</p><p>There are commonly three domains: N-terminal, middle (<db_xref db="INTERPRO" dbkey="IPR013808"/>) and C-terminal (<db_xref db="INTERPRO" dbkey="IPR013807"/>). This entry represents the N-terminal domain found in transglutaminases.</p> Transglutaminase, N-terminal