Transglutaminases are a family of enzymes () that catalyze the formation of a covalent bond between a free amine group (e.g., protein- or peptide-bound lysine) and the gamma-carboxamid group of protein- or peptide-bound glutamine. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation.Transglutaminases were first described in 1959. . The exact biochemical activity of transglutaminases was discovered in blood coagulation protein factor XIII in 1968.
Eight transglutaminases have been characterised.
Mechanism of action
Transglutaminases form extensively cross-linked, generally insoluble protein polymers. These biological polymers are indispensable for the organism in order 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.