The Firefly luciferase is a genetically modified variant derived from the Luciferase of Diaphanes pectinealis endemic to Yunnan province, China. It has been modified to provide enhanced stability compared to the normal phenotype of Photinus pyralis as well as a broader and more physiologically relevant effective pH range. Luciferase has been used as a sensitive reporter for studying gene regulation and function. Firefly luciferase catalyzes the oxidative carboxylation of luciferin, a reaction with the highest efficiency of any known bioluminescence reaction.