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Echinenone may be used as an external standard for the extraction of carotenoid from plasma samples. It may also been used as an internal standard, added to samples for extraction and quantification.

ChEBI: A carotenone that is beta-carotene in which the 4 position has undergone formal oxidation to afford the corresponding ketone. Isolated as orange-red crystals, it is widely distributed in marine invertebrates.

Echinenone is a carotenoid with a conjugated carbonyl group. Echinenone (4-keto-β-carotene) is a monoketo compound, is an intermediate between β-carotene and canthaxanthin in animals. It is one of the major carotenoids of Anabaena sp., and also present in Micrococcus roseus. It is located in the thylakoid membrane of Anabaena. The conversion of β-carotene to echinenone is catalysed by CrtO, a β-carotene ketolase.

Echinenone binds to glocobacter rhodopsin and functions as a light harvesting antenna in Gloeobacter violaceous.

Purify β,β-caroten-4-one by chromatography on partially deactivated alumina or magnesia, or by using a thin layer plate of silica gel G with 4:1 cyclohexane/diethyl ether as the developing solvent. Recrystallise it from *C6H6/MeOH. Store it in the dark at -20o. The oxime crystallises from *C6H6 with m 208o. [Beilstein 7 III 2858, 7 IV 1881.]