EC Explorer

1.13.11.63

β-carotene 15,15′-dioxygenase

β-carotene + O₂ = 2 all-trans-retinal

blh (gene name), BCO1 (gene name), BCDO (gene name), carotene dioxygenase, carotene 15,15′-dioxygenase, BCMO1 (misleading), β-carotene 15,15′-monooxygenase (incorrect)

β-carotene:oxygen 15,15′-dioxygenase (bond-cleaving)

Requires Fe²⁺. The enzyme cleaves β-carotene symmetrically, producing two molecules of all-trans-retinal. Both atoms of the oxygen molecule are incorporated into the products [8]. The enzyme can also process β-cryptoxanthin, 8′-apo-β-carotenal, 4′-apo-β-carotenal, α-carotene and γ-carotene in decreasing order. The presence of at least one unsubstituted β-ionone ring in a substrate greater than C₃₀ is mandatory [5]. A prokaryotic enzyme has been reported from the uncultured marine bacterium 66A03, where it is involved in the proteorhodopsin system, which uses retinal as its chromophore [6,7].

created 2012 (EC 1.14.99.36 created 1972 as EC 1.13.11.21, transferred 2001 to EC 1.14.99.36, incorporated 2015), modified 2016