The luciferase-luciferin bioluminescent system provides a highly sensitive and efficient tool for detecting gene expression In the presence of ATP oxygen and magnesium ions firefly luciferase catalyzes the oxidation reaction of luciferin into oxyluciferin accompanied by the emission of bioluminescence at about 560 nm This bioluminescence signal can be detected using a luminometer or liquid scintillation counter The Single Firefly Luciferase Reporter Gene Assay Kit allows direct quantification of intracellular firefly luciferase activity via chemiluminescence without the need for washing or harvesting cells This assay is a one-step detection kit providing exceptional sensitivity high signal stability and ease of use The luciferase detection reagent included in this kit can be directly added to cultured cells at equal volumes to the medium This assay is also suitable for measurements of previously lysed or stored cell samples