stabilize tissues

ABSTRACT Transglutaminases catalyze the posttrans-lational modification of proteins by transamidation of available glutamine residues. This action results primarily in the formation of e-(’y-glutamyl)lysine cross-links but includes the incorporation of polyamines into suitable protein substrates as well. The covalent isopeptide cross-link is stable and resistant to proteolysis, thereby increas-ing the resistance of tissue to chemical, enzymatic, and mechanical disruption. The plasma transglutaminase, factor XIIIa, is formed at sites of blood coagulation and impedes blood loss by stabilizing the fibrin clot. The squamous epithelium constituting the protective callus layer of skin is formed by the action of keratinocyte trans-glutaminase (TGK) and epidermal transglutaminase (TG). The tissue transglutaminase (TG) is a cytoplas