The NAD⁺-dependent DNA Ligase Assay Kit is to measure the DNA ligase product in which the diphosphodiester bond is formed at the single stand break of a duplex DNA substrate. The ligase reaction is monitored by the fluorescence intensity at 535 nm. The assay is in 96-well plate format and can be used for screening inhibitors of DNA ligases from gram-positive (such as S. pneumoniae) and gram-negative (such as E. coli) bacteria. Each kit includes the assay buffer, DNA substrate, Reagent D and the fluorescence dye for 100 assays. Reagent T is used to stop the reaction and denature the DNA at the end of the ligase reaction.