Green Fluorescent Protein
The green fluorescent protein (GFP) is a protein from the jellyfish Aequorea victoria and the sea pansy that fluoresces green when exposed to blue light. In cell and molecular biology, its gene is frequently used as a reporter of expression. In modified forms it has been used to make biosensors.
The wild type GFP from Aequorea victoria has a major excitation peak at a wavelength of 395 nm and a minor one at 475 nm. Its emission peak is at 509 nm which is in the lower green portion of the visible spectrum. The GFP from the sea pansy has a single major excitation peak at 498 nm.
Some mutants of the GFP gene have been produced with increased fluorescence. The major excitation peak has been shifted to 490 nm with the peak emission kept at 509 nm.
