LDH Cell Proliferation & Cytotoxicity Assay Kit

Lactate dehydrogenase (LDH) is present intracellularly and, under normal circumstances, cannot penetrate the cell membrane. However, when cells are damaged, LDH is released into the culture medium due to changes in cell membrane permeability. The released LDH catalyzes lactate production by converting oxidized coenzyme I (NAD+) to reduced coenzyme I (NADH). NADH then reduces iodonitrovinol chloride (INT) via the hydrogen donor phenazine dimethyl sulfate (PMS) to form a colored methyl compound with an absorption peak at 490 nm. Therefore, LDH activity can be quantified colorimetrically, and the absorbance reading can also be used to monitor cell necrosis.