Discovery of Green Fluorescent Protein

The bioluminescent jellyfish Aequorea emits green light from its light organs that contain aequorin and a green fluorescent protein. Aequorin emits blue light by reacting with calcium ions. In the jellyfish, however, the light energy produced is transferred from aequorin to the green fluorescent protein, resulting in the emission of green light from the latter. The course of discovering the green fluorescent protein is described.