Aequorea victoria
Aequorin is a calcium-activated photoprotein isolated from the hydrozoan "Aequorea victoria". Though the bioluminescence was studied decades before, the protein was isolated in 1962 from the animal by Osamu Shimomura. In the animals, the protein occurs together with the green fluorescent protein to produce green light by resonant energy transfer, while aequorin by itself generates blue light.