Transglutaminase (转谷氨酰胺酶)

Transglutaminases are Ca^²⁺-dependent enzymes that catalyze post-translational modifications of proteins by deamidation, transamidation, or esterification, transferring the γ-carboxamide group of protein-bound L-glutamine to primary amines. The transglutaminase superfamily includes TGM1-7 and Factor XIIIA, with Transglutaminase 2 (TG2), also known as tissue transglutaminase (tTG), being the most abundant and extensively studied member. TG2 plays diverse roles across tissues and is highly expressed in the liver and cytosol, while other isoforms exhibit tissue-specific expression: TG1, TG3, and TG5 in epithelial tissues; TG4 in the prostate gland; Factor XIII (FXIII) in blood; TG6 in the brain, lungs, and testis; and TG7 predominantly in the testis and lungs. TG2 has been implicated in a wide range of human diseases, including preeclampsia, hypertension, cardiovascular disease, organ fibrosis, cancer, neurodegenerative disorders such as Alzheimer's disease, and celiac disease, where it acts as a key autoantigen. This enzyme family’s functional diversity and pathological relevance make it a critical focus for therapeutic research^[1][2].