In vitro biosynthesis of xanthophylls by cell extracts of a green alga Chlorococcum | [Biosynthese in vitro de xanthophylles par des extraits cellulaires de l'algue verte Chlorococcum]
2001
Beihui, L. (National University of Singapore (Singapour). Faculty of Medicine, Department of Microbiology) | Kun, L.Y.
The ability of a cell-free carotenogenic system from the green alga Chloroccocum sp. to convert non-radiolabelled beta-carotene into echinenone, canthaxanthin and other endogenous xanthophylls was exploited. Carotenogenic activities of this in vitro system varied with different introductions of beta-carotene as substrate. Optimal activities were obtained when beta-carotene was provided in chloroform (1 % v/v) and cholic acid (0.1 %, w/v) as well as when L-alpha-phosphatidylcholine (100-200 micro-g per incubation) was present in the incubation mixture. The present investigation also indicated that oxygen was essential for the conversions. The effects of both dioxygenase cofactors and monooxygenase cofactors were presented. It was found that a dioxygenase cofactor mixture of Fe2+, ascorbic acid and 2-oxoglutarate was required to the carotenogenic activities.
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