Transglutaminases (TGs) are Ca²⁺and thiol-dependent enzymes that catalyze posttranslational modifications ofproteins. These covalent reactions include formation of isopeptide linkagesbetween the carboxamide groups of protein-bound glutamine residues and ε-aminogroups of protein-bound lysine and polyamine residues, hydrolysis and esterification of glutamine residues. Family of TGs includes atleast nine members: TG 1-7, coagulation factor XIIIa, and the keratinocytemembrane bound TG form. TG hasattracted considerable interest as a potential drugtarget. Its activity is thought to contribute to Alzheimer disease,Parkinson disease, Huntington disease, and supranuclear palsy.

SensoLyte^®Transglutaminase Activity Assay Kit provides a convenient assay for the highthroughput screening of TG modulators and inhibitors. TG catalyzes covalentbond formation between a free amine group of poly-D-lysine, which is coated onthe plate surface, and γ-carboxamide group of glutamine in biotin-TVQQELpeptide substrate. The reaction immobilizes biotin-conjugated peptide to theplate surface. The amount of immobilized biotin is determined usingstreptavidin-horseradishperoxidase (HRP), 10-Acetyl-3,7-dihydroxyphenoxazine(ADHP), and hydrogen peroxide (H₂O₂).The non-fluorescent ADHP is oxidized to the strong fluorescent resorufin in thepresence of H₂O₂ by peroxidases, such as HRP. The fluorescence intensity of resorufin isproportional to the activity of TG in a sample. Assay is performed in aconvenient 96-well microplate format.