The discovery of aequorin and green fluorescent protein

We discovered aequorin and green fluorescent protein (GFP) in 1961 from the same species of jellyfish (Shimomura et al 1962). Our target was a luminescent substance, aequorin, and GFP was isolated as a by-product of aequorin owing to its bright conspicuous fluorescence. Both are unusual proteins but they had no particular importance when we first reported them. Their importance became apparent in the course of studies, and now, 40 years after their discovery, they are well known and widely used, aequorin as a calcium probe and GFP as a marker protein. In the characterization of these proteins, information obtained from the bioluminescence of the ostraco