LUC, also known as luciferase. LUC catalyzes the oxidative decarboxylation of coelenterazine in the presence of dissolvedoxygen to yield oxyluciferin, CO2, and blue light. In vivo, the excited state luciferin-luciferase complex undergoes the process of noradiative energy transfer to an accessory protein, green fluorescent protein, which results in green bioluminescence. In vitro, it emits blue light in the absence of any green fluorescent protein. Recombinant renilla reniformis LUC, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.