Caspase (Cysteine-requiring Aspartate Protease) is a protease family that plays an important role in the process of apoptosis. Caspase 9 (also known as ICE-LAP6, or mch6) is considered to be a caspase in the upstream of apoptotic signal transduction. When mitochondria release cytochrome c, Caspase 9 can form complex with cytochrome c and Apaf1, and be activated at the same time. Activated Caspase 9 can activate Caspase 3 which is the key enzyme of cell apoptosis, thereby promoting subsequent apoptotic signals. Caspase 9 exists in the form of prozyme in the normal state and has no activity. However, Caspase 9 is activated in the apoptotic stage and participates in the apoptotic process.\nThis kit is used to conjugate Caspase 9 sequence-specific peptides acetyl-Leu-Glu-His-Asp p-nitroanilide (Ac-LEHD-pNA) to yellow group p-nitroaniline (pNA). When the substrate is cut by Caspase 9, the yellow group pNA is dissociated. pNA has an absorption peak at 405 nm. Measure the OD value at 405 nm and then Caspase 9 activity can be calculated accordingly