Luciferase is an oxidative enzyme that can produce bioluminescence with addition of luciferin, but doesn’t need an external light source unlike fluorescent proteins. Photo emission can be detected directly by light sensitive devices. Such as luminometers or modified microscopes. Luciferase is widely used in many fields of biological research, such as transcriptional activity, kinase or other enzyme activity, cellular ATP level, and whole animal imaging.
Green fluorescent protein (GFP) is a β - barrel protein 1 composed of 238 amino acids with a molecular weight of approximately 27 kDa. GFP was isolated from the crystal jellyfish Aequorea Victoria. GFP can convert the blue fluorescence emitted by jellyfish luminescent protein through chemical reactions into green fluorescence through energy transfer. The excitation wavelength of GFP is 488 nm, and there is an emission peak at approximately 507 nm.