Subtopic 4.4: Enzyme Assay
The enzyme assay is used to monitor passaging of lactate dehydrogenase (LDH), due to loss of cell membrane integrity when cells are exposed to cytotoxic compounds. LDH reduces NAD to NADH which generates a color change by interaction with a specific probe (Figure 4a). In other enzyme assay, Adenosine triphosphate (ATP )-based assay combined with bioluminescent assay are used to measure cytotoxicity of the cells in which ATP is the reagent for the luciferase reaction (Figure 4b).