Transglutaminase 2 (TGM2), encoded by the TGM2 gene, is belongs to the family of transglutaminases that catalyze the posttranslational modification of proteins via calcium dependent cross-linking reactions. In addition to its function in protein cross-linking, TGM2 is also capable of hydrolyzing both GTP and ATP and has intrinsic kinase activity. TGM2 has been implicated in a variety of human diseases including celiac disease, inclusion body myositis, atherosclerosis, and neurodegenerative diseases. The activity of recombinant human TGM2 is measured by its ability to cleave a synthetic peptide Benzyloxycarbonyl-Gln-Gly and NH2OH in the assay buffer 200 mM MES, 10 mM DTT, 10 mM CaCl2, 100 mM Hydroxylamine Hydrochloride, pH 6.0. The rhTGM2 is diluted to 12.5 ug/ml in assay buffer. Loading into a clear well plate 50 μL of 12.5 ug/mL rhTGM2 and start the reaction by adding 50 μL of 100 mM substrate, with a substrate blank containing 50 μL assay buffer, 50 μL substrate, and no rhTGM2. Incubated at 37 °C for 2 hours and stop the reaction with 400 ul stop solution of 0.37 M FeCl3, 0.67 M HCl，0.2 M Trichloroacetic Acid. Centrifuge at 2000 rpm for 2 minutes and then load 200 ul of the supernatant into a plate and read at 525 nm (absorbance) in endpoint mode. The specific activity of recombinant human TGM2 is > 800 pmol/min/μg.