Aequorin

Description:Aequorin is a photoprotein isolated from luminescent jellyfish (like various Aequorea species e.g. Aequorea victoria) and a variety of other marine organisms.[1] It was originally isolated from the coelenterate by Osamu Shimomura.Since the 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. Cultured cells expressing the aequorin gene can effectively synthesize aequorin: however recombinant expression only yields the apoprotein, therefore it is necessary to add coelenterazine into the culture medium of the cells to obtain a functional protein and thus use its blue light emission to measure Ca2+ concentration. Coelenterazine is a hydrophobic molecule, and therefore is easily taken up across plant and fungal cell walls, as well as the plasma membrane of higher eukaryotes, making aequorin suitable as a (Ca2+ reporter) in plants, fungi and mammalian cells.