LDH Cytotoxicity Assay Kit

Lactate dehydrogenase (LDH) is an intracellular enzyme widely present in the cytoplasm and plays a key role in glycolysis by catalyzing the reversible conversion between lactate and pyruvate. When the plasma membrane is damaged, LDH is rapidly released into the cell culture supernatant, serving as a hallmark of cell apoptosis, necrosis, or other forms of cell injury. Therefore, LDH activity in the supernatant is a vital biomarker for evaluating membrane integrity and cytotoxicity, and it is widely used in studies related to drug toxicity, cell viability, and immune cell-mediated cytolysis.This assay kit is based on the LDH-catalyzed reaction in which lactate is converted to pyruvate with the concomitant reduction of NAD⁺to NADH. The resulting NADH then reacts with INT to produce an orange-red colored compound, formazan. Formazan exhibits a high absorbance at 490 nm, which is positively correlated with LDH activity. Thus, by measuring the absorbance, LDH activity can be quantitatively assessed, indirectly reflecting the extent of cell damage or apoptosis.