What does aequorin mean?
Aequorin is a photoprotein originally isolated from the crystal jellyfish, Aequorea victoria, a small jellyfish abundant along the Pacific coast of North America. Unlike fluorescent proteins, which simply re-emit absorbed light, aequorin generates light through a chemical reaction: when calcium ions bind to it, the protein oxidizes its bound luciferin substrate, coelenterazine, releasing a flash of blue light. This property makes aequorin an exceptionally useful tool for measuring calcium concentrations inside living cells, since each binding event produces a detectable photon signal. Scientists have also produced recombinant forms of the protein for use in assays and biosensors. The word derives from the Latin aequor, meaning the surface of the sea, reflecting the animal it came from. Although strictly a term of biochemistry rather than everyday vocabulary, aequorin occupies an important place in the history of bioluminescence research and contributed to work recognized with the Nobel Prize in Chemistry in 2008.
nounA calcium-binding photoprotein found in the jellyfish Aequorea victoria that emits blue light when it binds calcium ions; used extensively as a biological marker and in imaging techniques.
- The calcium-activated photoprotein naturally occurring in Aequorea victoria that produces blue bioluminescence.
- Any recombinant or synthetic preparation of this protein used as a laboratory tool for detecting intracellular calcium.
"The researchers used aequorin to measure tiny fluctuations of calcium inside living cells."
"When calcium floods into the cell, aequorin flashes with a brief pulse of blue light."
"Commercial kits use recombinant aequorin as a sensitive label in immunoassays."
Rarely pluralized; used mainly when referring to distinct isoforms or engineered variants of the protein.
"Several engineered aequorins have been developed with altered calcium sensitivity."
This glowing protein was pulled from a crystal jellyfish off the U.S. West Coast — and it helped win a Nobel Prize.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of aequorin
Aequorin was named by the scientists who isolated it from Aequorea victoria in the 1960s, drawing on the Latin noun aequor, meaning 'the flat surface of the sea' — itself related to aqua, water. The suffix '-in' follows the standard convention for naming proteins. Its discovery grew out of Osamu Shimomura's studies of jellyfish bioluminescence, work later honored with the 2008 Nobel Prize in Chemistry alongside Martin Chalfie and Roger Tsien.
How aequorin is actually used
Strictly a technical term confined to biochemistry, cell biology, and bioluminescence research; rarely encountered outside scientific literature. Usually treated as an uncountable substance name, though specific engineered variants may be referred to individually.
Easily confused with aequorin
Green fluorescent protein (GFP) is a separate protein from the same jellyfish that fluoresces green on its own, whereas aequorin emits blue light only upon binding calcium.