Abstract
THE protein aequorin, from the jellyfish Aequorea, emits bluish light in aqueous solution on addition specifically of calcium or strontium; the necessary energy of more than 60 kcalories/mole at the peak wavelength is evidently provided by an intramolecular reaction which is accompanied by a change in absorption spectrum and yields a blue fluorescent reaction product1,2. The extreme sensitivity to Ca2+, much more than to Sr2+, provides a basis for quick microdetermination of Ca2+ in biological fluids3 and has been used in detecting the relation of Ca2+ to contraction of single muscle fibres4,5 and to activity of mitochondria6. The chief properties of aequorin, including the molecular weight (m.w.) of 30,000 by sedimentation, diffusion or 32,000 by amino-acid composition, have been reported7. The kinetics of the light-emitting reaction have also been studied8.
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SHIMOMURA, O., JOHNSON, F. Calcium Binding, Quantum Yield, and Emitting Molecule in Aequorin Bioluminescence. Nature 227, 1356–1357 (1970). https://doi.org/10.1038/2271356a0
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DOI: https://doi.org/10.1038/2271356a0
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