|PROSITE documentation PDOC00473|
Transglutaminases (EC 18.104.22.168) (TGase) [1,2] are calcium-dependent enzymes that catalyze the cross-linking of proteins by promoting the formation of isopeptide bonds between the γ-carboxyl group of a glutamine in one polypeptide chain and the epsilon-amino group of a lysine in a second polypeptide chain. TGases also catalyze the conjugation of polyamines to proteins.
The best known transglutaminase is blood coagulation factor XIII, a plasma tetrameric protein composed of two catalytic A subunits and two non-catalytic B subunits. Factor XIII is responsible for cross-linking fibrin chains, thus stabilizing the fibrin clot.
Other forms of transglutaminases are widely distributed in various organs, tissues and body fluids. Sequence data is available for the following forms of TGase:
A conserved cysteine is known to be involved in the catalytic mechanism of TGases.
The erythrocyte membrane band 4.2 protein, which probably plays an important role in regulating the shape of erythrocytes and their mechanical properties, is evolutionary related to TGases. However the active site cysteine is substituted by an alanine and the 4.2 protein does not show TGase activity.Last update:
December 2004 / Pattern and text revised.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Ichinose A., Bottenus R.E., Davie E.W.|
|Title||Structure of transglutaminases.|
|Source||J. Biol. Chem. 265:13411-13414(1990).|
|2||Authors||Greenberg C.S., Birckbichler P.J., Rice R.H.|
|Title||Transglutaminases: multifunctional cross-linking enzymes that stabilize tissues.|
|Source||FASEB J. 5:3071-3077(1991).|