ID   1.13.12.24
DE   calcium-regulated photoprotein.
AN   aequorin.
AN   berovin.
AN   Ca(2+)-regulated photoprotein.
AN   calcium-activated photoprotein.
AN   clytin.
AN   halistaurin.
AN   mitrocomin.
AN   mnemiopsin.
AN   obelin.
AN   vialidin.
CA   apo-[aequorin] + 3 Ca(2+) + coelenterazine + O2 = [excited state blue
CA   fluorescent protein] + CO2.
CC   -!- Ca(2+)-regulated photoproteins are found in a variety of
CC       bioluminescent marine organisms, mostly coelenterates, and are
CC       responsible for their light emission.
CC   -!- The best studied enzyme is from the jellyfish Aequorea victoria.
CC   -!- The enzyme tightly binds the imidazolopyrazinone derivative
CC       coelenterazine, which is then peroxidized by oxygen.
CC   -!- The hydroperoxide is stably bound until three Ca(2+) ions bind to the
CC       protein, inducing a structural change that results in the formation
CC       of a 1,2-dioxetan-3-one ring, followed by decarboxylation and
CC       generation of a protein-bound coelenteramide in an excited state.
CC   -!- The calcium-bound protein-product complex is known as a blue
CC       fluorescent protein.
CC   -!- In vivo the energy is transferred to a green fluorescent protein
CC       (GFP) by Foerster resonance energy transfer.
CC   -!- In vitro, in the absence of GFP, coelenteramide emits a photon of
CC       blue light while returning to its ground state.
//