TGM2 also known as Protein-glutamine gamma-glutamyltransferase 2. Transglutaminases are enzymes that catalyze the crosslinking of proteins by epsilon-gamma glutamyl lysine isopeptide bonds. While the primary structure of transglutaminases is not conserved, they all have the same amino acid sequence at their active sites and their activity is calcium-dependent. TGM2 acts as a monomer, is induced by retinoic acid, and appears to be involved in apoptosis. Recombinant human TGM2, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.