Granzyme B (GZMB, EC number 3.4.21.79) also known as Granzyme-2 is a serine protease stored in the granules of activated cytotoxic T cells and NK cells. Upon target cell contact, Granzyme B is directionally exocytosed and with the assistance of perforin enters the target cell. With its unique substrate specificity (Granzyme B prefers an aspartic acid residue at the P1 site of its substrates), Granzyme B processes and activates various pro-caspases thereby inducing apoptosis in the target cell. In BioVision's Granzyme B Inhibitor Screening Kit, active human Granzyme B enzyme hydrolyzes the specific substrate to release the quench of fluorescent group, which can be detected fluorometrically at Ex/Em = 380/500 nm. In the presence of potent Gra