Transglutaminase (TG)

A transglutaminase is an enzyme that catalyzes the formation of a covalent bond between a free amine group (e.g., protein- or peptide-bound lysine) and the acyl group at the end of the side chain of protein- or peptide-bound glutamine. The reaction also produces a molecule of ammonia. Such an enzyme is classified as EC 2.3.2.13. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis). Transglutaminases form extensively cross-linked, generally insoluble protein polymers. These biological polymers are indispensable for the organism to create barriers and stable structures. Examples are blood clots (coagulation factor XIII), as well as skin and hair. The catalytic reaction is generally viewed as being irreversible, and must be closely monitored through extensive control mechanisms. A collection of the transglutaminase substrate proteins and interaction partners is accessible in the TRANSDAB database.