LDH Cytotoxicity Assay Kit

The LDH Cytotoxicity Assay Kit is a colorimetric assay kit detects lactate dehydrogenase activity released during cytotoxicity or in other samples.

The LDH Cytotoxicity Assay Kit, also known as the LDH Release Assay Kit, is a colorimetric method based on a diaphorase-catalyzed INT reaction for measuring lactate dehydrogenase (LDH) activity. During apoptosis or necrosis, disruption of the plasma membrane leads to the release of cytoplasmic enzymes into the culture medium, including the relatively stable enzyme LDH. Quantification of LDH released into the extracellular medium therefore provides a reliable measure of cell membrane damage and cytotoxicity.

In this assay, LDH catalyzes the conversion of lactate, reducing NAD⁺ to NADH. NADH subsequently reacts with INT (2-p-iodophenyl-3-nitrophenyl tetrazolium chloride) in the presence of diaphorase to regenerate NAD⁺ and produce a highly colored formazan product. Formazan exhibits a strong absorbance at 490 nm, enabling quantitative detection of LDH activity in cell culture supernatants or cell lysates. The absorbance signal is directly and linearly proportional to LDH activity and cytotoxicity level.