For measurement of LDH activity as an indicator of cell death.

• A colorimetric, non-radioactive assay for assessing drug-induced cytotoxicity​
• LDH release from the cytosol into the medium catalyzes a color-forming reaction
• Detect lysis of 10,000 to 200,000 cells per well
• Alternative to ⁵¹Cr-release assays

Necrosis is accompanied by mitochondrial swelling and increased plasma membrane permeability, while apoptosis involves an articulated breakdown of the cell into membrane-bound apoptotic bodies. Lactate dehydrogenase (LDH) is a soluble cytosolic enzyme that is released into the culture medium following loss of membrane integrity resulting from cell- or compound-induced cytotoxicity. LDH activity, therefore, can be used as an indicator of cell membrane integrity and serve as a general means to assess cell viability by measuring plasma membrane permeability. Cayman's LDH Cytotoxicity Assay Kit measures cell death in response to chemical compounds or environmental factors using a coupled two-step reaction. In the first step, LDH catalyzes the reduction of NAD⁺ to NADH and H⁺ by oxidation of lactate to pyruvate. In the second step of the reaction, diaphorase uses the newly-formed NADH and H⁺ to catalyze the reduction of a tetrazolium salt (INT) to highly-colored formazan which absorbs strongly at 490 to 520 nm.