Correlation Engine 2.0
Clear Search sequence regions


  • BCO1 (6)
  • BCO2 (4)
  • cancer (1)
  • carotenoid (11)
  • catalysis (1)
  • dioxygenases (2)
  • diseases and (1)
  • homeostasis (1)
  • humans (3)
  • knockout mice (2)
  • lipid (1)
  • lutein (1)
  • mammals (1)
  • mice (1)
  • oxygen (1)
  • oxygenases (4)
  • phenotypes (1)
  • protein human (2)
  • risk diseases (1)
  • vertebrate (3)
  • vitamin (2)
  • zeaxanthin (1)
  • Sizes of these terms reflect their relevance to your search.

    Mammals and higher vertebrates including humans have only three members of the carotenoid cleavage dioxygenase family of enzymes. This review focuses on the two that function as carotenoid oxygenases. β-Carotene 15,15'-dioxygenase (BCO1) catalyzes the oxidative cleavage of the central 15,15' carbon-carbon double of β-carotene bond by addition of molecular oxygen. The product of the reaction is retinaldehyde (retinal or β-apo-15-carotenal). Thus, BCO1 is the enzyme responsible for the conversion of provitamin A carotenoids to vitamin A. It also cleaves the 15,15' bond of β-apocarotenals to yield retinal and of lycopene to yield apo-15-lycopenal. β-Carotene 9',10'-dioxygenase (BCO2) catalyzes the cleavage of the 9,10 and 9',10' double bonds of a wider variety of carotenoids, including both provitamin A and non-provitamin A carotenoids, as well as the xanthophylls, lutein and zeaxanthin. Indeed, the enzyme shows a marked preference for utilization of these xanthophylls and other substrates with hydroxylated terminal rings. Studies of the phenotypes of BCO1 null, BCO2 null, and BCO1/2 double knockout mice and of humans with polymorphisms in the enzymes, has clarified the role of these enzymes in whole body carotenoid and vitamin A homeostasis. These studies also demonstrate the relationship between enzyme expression and whole body lipid and energy metabolism and oxidative stress. In addition, relationships between BCO1 and BCO2 and the development or risk of metabolic diseases, eye diseases and cancer have been observed. While the precise roles of the enzymes in the pathophysiology of most of these diseases is not presently clear, these gaps in knowledge provide fertile ground for rigorous future investigations. This article is part of a Special Issue entitled Carotenoids: Recent Advances in Cell and Molecular Biology edited by Johannes von Lintig and Loredana Quadro. Copyright © 2020 Elsevier B.V. All rights reserved.

    Citation

    Earl H Harrison, Rachel E Kopec. Enzymology of vertebrate carotenoid oxygenases. Biochimica et biophysica acta. Molecular and cell biology of lipids. 2020 Nov;1865(11):158653

    Expand section icon Mesh Tags

    Expand section icon Substances


    PMID: 32035229

    View Full Text