The biosynthesis of astaxanthin. XVIII. The incorporation and transformation of carotenoids in the goldfish
Date of Original Version
1. 1. Additional evidence is presented to prove that astaxanthin is formed from β-carotene through the pathway β-carotene → isocryptoxanthin ester → echinenone → 4-hydroxy-4′-keto-β-carotene ester → canthaxanthin → astaxanthin ester. 2. 2. Intermediate compounds were fed individually to depleted goldfish and their transformation was followed. 3. 3. Isocryptoxanthin, echinenone and canthaxanthin markedly increased the astaxanthin content of the fish, showing that they could all be transformed to astaxanthin. In addition, isocryptoxanthin promoted synthesis of echinenone, isozeaxanthin and 4-hydroxy-4′-keto-β-carotene. Echinenone led to the production of 4-hydroxy-4′-keto-β-carotene and canthaxanthin. 4. 4. Isozeaxanthin fed at the level of 0.5 μg. per g. of food was not metabolized further. At a higher concentration (2 mg. per g. food), it was converted to 4-hdyroxy-4′-keto-β-carotene but it did not raise the astaxanthin content of the fish. © 1974.
International Journal of Biochemistry
Rodriguez, Delia B., K. L. Simpson, and C. O. Chichester. "The biosynthesis of astaxanthin. XVIII. The incorporation and transformation of carotenoids in the goldfish." International Journal of Biochemistry 5, 2 (1974): 157-166. doi:10.1016/0020-711X(74)90145-1.