Carotenoid oxygenase explained

Carotenoid oxygenases are a family of enzymes involved in the cleavage of carotenoids to produce, for example, retinol, commonly known as vitamin A. This family includes an enzyme known as RPE65 which is abundantly expressed in the retinal pigment epithelium where it catalyzed the formation of 11-cis-retinol from all-trans-retinyl esters.

Carotenoids such as beta-carotene, lycopene, lutein and beta-cryptoxanthin are produced in plants and certain bacteria, algae and fungi, where they function as accessory photosynthetic pigments and as scavengers of oxygen radicals for photoprotection. They are also essential dietary nutrients in animals. Carotenoid oxygenases cleave a variety of carotenoids into a range of biologically important products, including apocarotenoids in plants that function as hormones, pigments, flavours, floral scents and defence compounds, and retinoids in animals that function as vitamins, chromophores for opsins and signalling molecules.[1] Examples of carotenoid oxygenases include:

Members of the family use an iron(II) active center, usually held by four histidines.

Human proteins containing this domain

BCO2

BCO1; RPE65;

Further reading

Notes and References

  1. Wyss A . Carotene oxygenases: a new family of double bond cleavage enzymes . The Journal of Nutrition . 134 . 1 . 246S–250S . January 2004 . 14704328 . 10.1093/jn/134.1.246S . free .
  2. Tan BC, Joseph LM, Deng WT, Liu L, Li QB, Cline K, McCarty DR . Molecular characterization of the Arabidopsis 9-cis epoxycarotenoid dioxygenase gene family . The Plant Journal . 35 . 1 . 44–56 . July 2003 . 12834401 . 10.1046/j.1365-313X.2003.01786.x . free .
  3. Eriksson J, Larson G, Gunnarsson U, Bed'hom B, Tixier-Boichard M, Strömstedt L, Wright D, Jungerius A, Vereijken A, Randi E, Jensen P, Andersson L . 6 . Identification of the yellow skin gene reveals a hybrid origin of the domestic chicken . PLOS Genetics . 4 . 2 . e1000010 . February 2008 . 18454198 . 2265484 . 10.1371/journal.pgen.1000010 . Michel . Georges . free .
  4. Kloer DP, Ruch S, Al-Babili S, Beyer P, Schulz GE . The structure of a retinal-forming carotenoid oxygenase . Science . 308 . 5719 . 267–9 . April 2005 . 15821095 . 10.1126/science.1108965 . 6318853 . 2005Sci...308..267K .