Transglutaminases (Tgases) are a widely distributed group of enzymes that catalyse the post-translational modification of proteins by the formation of isopeptide bonds. This occurs either through protein cross-linking via epsilon-(gamma-glutamyl)lysine bonds or through incorporation of primary amines at selected peptide-bound glutamine residues. The cross-linked products, often of high molecula...

All transglutaminases share the common enzymatic activity of transamidation, or the cross-linking of glutamine and lysine residues to form N epsilon (gamma-glutamyl) lysyl isopeptide bonds. The plasma proenzyme factor XIII is responsible for stabilizing the fibrin clot against physical and fibrinolytic disruption. Another member of the transglutaminase family, tissue transglutaminase or TG2 is ...

BACKGROUND/AIMS The transglutaminases (TG2 and factor XIIIa) may contribute to the stability of arteries by cross-linking a variety of substrates, including extracellular matrix proteins and protease inhibitors. The preferred substrates have never been determined, however. METHODS We used an amine donor, 5-biotinamidopentylamine, that is covalently linked to acceptor glutamine residues, to de...

Thirteen recombinant alpha A-crystallin mutants were constructed that differed in the type of amino acid residue directly preceding the sole amine donor lysine for transglutaminases in this protein. The capacity of these mutants to be cross-linked to amine acceptor substrates by tissue transglutaminase and factor XIII was assessed. Two different biotinylated glutamine-containing oligopeptides w...

The transfer reaction of [W!]methylamine into the acetylated B chain of oxidized insulin as catalyzed by several transglutaminases has been studied at pH ‘7.5 in the presence of calcium ion. The only radioactive product of the transfer reaction with each transglutaminase was identified as peptide-bound y-glutamic acid methylamide. Initial velocity and product inhibition patterns for the human p...

Fertilization is accompanied by the construction of an extracellular matrix that protects the new zygote. In sea urchins, this structure is built from glycoproteins residing at the egg surface and in secretory vesicles at the egg cortex. Four enzymatic activities are required for the transformation of these proteins into the mechanically and chemically resilient fertilization envelope: proteoly...

Transglutaminases are a family of enzymes that are known for their protein cross-linking abilities. Transglutaminases have been investigated very little in female reproductive tissues. We hypothesized that transglutaminase proteins were present and active in the virgin rat uterus and cervix. In both tissues, real time RT-PCR identified transglutaminase 1, 2, 3, and 4 mRNA, and immunohistochemis...