The bioluminometric AK Cytotoxicity Kit is based on the measurement of adenylate kinase (AK), a ubiquitous protein present in all cells that is rapidly released into the culture medium upon damage to the plasma membrane. The simple one-step procedure involves two chemical reactions. First, the adenylate kinase released from the damaged cells catalyses the conversion of ADP to ATP. The second reaction utilizes luciferase to catalyze a reaction between the ATP, oxygen, and luciferin producing light. The light can be measured using a luminometer or beta counter. This highly sensitive assay allows rapid quantitation of plasma membrane damage for evaluation of cell death or cytotoxicity events, and it is well suited for automation and high throughput.