Transglutaminases catalyze the formation of cross-links between the side chains of glutaminyl and lysyl residues of polypeptide to N epsilon-(gamma-L-glutamyl)-L-lysine. The resulting polymers are required to create barriers and stable structures of insoluble proteins in organisms. Several recent studies on various aspects of transglutaminases successfully used an anti-N epsilon (gamma-L-glutamyl)-L-lysine isopeptide antibody that can be order from antibodies-online.

The importance of transglutaminase is emphasized by the effects their malfunctioning has. Deficiency of the transglutaminase factor XIII for example predisposes to hemorrhage, i.e. increased bleeding risk. Recent research indicates that some neurological diseases like Huntington's, and Parkinson's may result from unusually high levels of tissue transglutaminase, leading to changes in protein structure.