Aequorin is a calcium-activated photoprotein isolated from the hydrozoan Aequorea victoria.
In the animal, the protein occurs together with the green fluorescent protein to produce green light by resonant energy transfer, while aequorin by itself generates blue light.
Apoaequorin, the protein portion of aequorin, is an ingredient in the dietary supplement Prevagen.
The US Federal Trade Commission (FTC) has charged the maker with false advertising for its memory improvement claims.
Aequorin is a holoprotein composed of two distinct units, the apoprotein that is called apoaequorin, which has an approximate molecular weight of 21 kDa, and the prosthetic group coelenterazine, the luciferin.
Apoaequorin is the enzyme produced in the photocytes of the animal, and coelenterazine is the substrate whose oxidation the enzyme catalyzes.
When coelenterazine is bound, it is called aequorin.
The protein is a member of the superfamily of the calcium-binding proteins.
Since its emitted light can be easily detected with a luminometer, aequorin has become a useful tool in molecular biology for the measurement of intracellular Ca2+ levels.
Apoaequorin is an ingredient in “Prevagen”, which is marketed by Quincy Bioscience as a memory supplement.
The US Federal Trade Commission (FTC) charged the maker with falsely advertising that the product improves memory, provides cognitive benefits, and is “clinically shown” to work.
The American Pharmacists Association warns that Apoaequorin “is unlikely to be absorbed to a significant degree; instead it degrades into amino acids”.