Firefly luciferase is widely used as a reporter for studying gene regulation and function, and for pharmaceutical screening. It is a very sensitive genetic reporter due to the absence of endogenous luciferase activity in mammalian cells or tissues.

Firefly luciferase is a 62000 dalton protein, which is active as a monomer and does not require subsequent processing for its activity. The enzyme catalyses ATP-dependent D-luciferin oxidation to oxyluciferin, producing light emission centered at 560 nm. This follows Michaelis-menten kinetics and, as a result, maximum light output is not achieved until the substrate and co-factors are present in large excess. When assayed under these conditions, light emitted from the reaction is directly proportional to the number of luciferase enzyme molecules.

Firefly luciferase assay kit is designed for simple and efficient quantitation of firefly luciferase reporter enzyme activity from cultured cells with high sensitivity and linearity. It features firefly assay buffer 2,0, which has better working solution stability compared to the original assay buffer.