Tissue Transglutaminase

Product Information

Tissue transglutaminase (tTG) is a ubiquitously expressed, calcium-dependent enzyme that plays key roles in extracellular matrix remodelling, wound healing, cell adhesion and intracellular signalling. Human tTG is a 687 amino acid protein with a molecular weight of approximately 80 kDa and comprises four structural domains: an N-terminal β-sandwich domain, a catalytic core domain and two C-terminal β-barrel domains.

tTG catalyses calcium-dependent transamidation reactions that cross-link glutamine and lysine residues and, under appropriate conditions, deamidates glutamine residues. In coeliac disease, tTG-mediated deamidation of gluten peptides generates immunogenic T-cell epitopes, making tTG the principal autoantigen in the disease. Increased tTG expression is observed in the intestinal mucosa of affected individuals, and circulating anti-tTG IgA autoantibodies are highly sensitive and specific biomarkers widely used for the diagnosis and monitoring of coeliac disease.

tTG exists in two distinct conformational states. In the compact, GTP-bound conformation, the C-terminal domains fold over the catalytic core, producing a catalytically inactive enzyme. Binding of Ca²⁺ induces a major conformational change, rotating the C-terminal domains to generate an extended, catalytically active structure in which both the active site and conformational epitopes become fully accessible.

AROTEC Tissue Transglutaminase antigen is full-length recombinant human tTG with a C-terminal His tag, expressed in Spodoptera frugiperda insect cells. The antigen is supplied in a storage buffer containing 10 mM EDTA to chelate Ca²⁺ and maintain tTG in its inactive, closed conformation during storage and transport. For optimal performance, the antigen should be diluted into a coating buffer containing 5–10 mM Ca²⁺ prior to immobilisation on ELISA plates or other surfaces. Calcium promotes conversion to the open conformation, maximising exposure of diagnostically relevant conformational epitopes and improving antibody recognition.

Clinical Indications

Coeliac Disease

Certificate of Analysis

Please log in to view certificates of analysis for this item

MSDS

References

1. Griffin M, Casadio R, Bergamini CM. Transglutaminases: Nature’s biological glues. Biochem J. 2002;368:377–396.
2. Wang Z, Griffin M. TG2, a novel extracellular protein with multiple functions. Amino Acids. 2012;42(2–3):939–949.
3. Gundemir S, Colak G, Tucholski J, Johnson GVW. Transglutaminase 2: a molecular Swiss army knife. Biochimica et Biophysica Acta. 2012;1823(2):406–419.
4. Liu S, Cerione RA, Clardy J. Structural basis for the guanine nucleotide-binding activity of tissue transglutaminase and its regulation of transamidation activity. Proceedings of the National Academy of Sciences USA. 2002;99(5):2743–2747.
5. Dieterich W, Ehnis T, Bauer M, et al. Identification of tissue transglutaminase as the autoantigen of celiac disease. Nature Medicine. 1997;3(7):797–801.
6. Korponay-Szabó IR, Troncone R, Discepolo V. Adaptive diagnosis of coeliac disease. Best Practice & Research Clinical Gastroenterology. 2015;29(3):381–398.
7. Adriaanse M, Leffler DA. Serum markers in the clinical management of celiac disease. Digestive Diseases. 2015;33(2):236–243.
8. Jang TH, Lee DS, Choi K, et al. Crystal structure of transglutaminase 2 with GTP complex and amino acid sequence evidence of evolution of the GTP binding site. PLoS One. 2014;9(9):e107005.
9. Di Venere A, Rossi A, De Matteis F, et al. Opposite effects of Ca²⁺ and GTP binding on tissue transglutaminase tertiary structure. Journal of Biological Chemistry. 2000;275(6):3915–3921.
10. D.M. Pinkas, et al., Transglutaminase 2 undergoes a large conformational change upon activation. PLoS Biol. 5 (12) (2007) e327.