The mechanisms of action and physiological functions of two calcium-activated enzyme families, the calpains and transglutaminases, are discussed: 1. Both enzymes work via a covalent acylenzyme intermediate. Calpains, as other papain-like proteases, have a Cys and His residue in the active site, which in the ground state tend to form a thiolate-imidazolium ion pair. In the active site of tranglu...

T he family of transglutaminases (TG) includes the plasma form factor XIIIa as well as the tissue transglutaminase (tTG) and keratinocyte transglutaminase (TGk). In particular, tTG reminds every gastroenterologist primarily of coeliac disease where tTG represents the key autoantigen. Disease induction is confined to tTG, a ubiquitous enzyme which is released from fibroblasts, endothelial, and i...

Celiac disease is a complex polygenic systemic disorder caused by dietary gluten exposure that selectively occurs in genetically susceptible people. The potential celiac defined the presence of disease-specific antibodies and compatible human leukocyte antigen but without histological abnormalities duodenal biopsies. At present, only treatment lifelong adherence to gluten-free diet. Despite its...

PURPOSE Proliferative vitreoretinopathy (PVR) is characterized by the development of epi- and subretinal fibrocellular membranes containing modified retinal pigment epithelial (RPE) cells among others. In the present study, the role of transglutaminases in accumulation of extracellular matrix (ECM) proteins in these membranes was investigated. Transglutaminases are enzymes capable of cross-link...

The cell envelope (CE) is a specialized structure that is important for barrier function in terminally differentiated stratified squamous epithelia. The CE is formed inside the plasma membrane and becomes insoluble as a result of cross-linking of constituent proteins by isopeptide bonds formed by transglutaminases. To investigate the earliest stages of assembly of the CE, we have studied human ...

Background and aims: Ulcerative colitis (UC) is characterised by refractory inflammatory ulceration and damage to the colon. The mechanisms underlying impaired healing have yet to be defined. As transglutaminase expression resulting in matrix protein cross linking is associated with increased wound healing in a rat model of colitis, we hypothesised that different types of transglutaminase might...

The role of tissue transglutaminase (tTG) in cancer development remains an important field of study. The aim of the current study was to understand the involvement of tTG in cancer and the inhibitory effect of cantharidinate on the expression of tTG in human colorectal cancer (CRC) using immunohistochemical and PCR analysis. The results showed that the expression of tTG increased in human CRC a...