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EC 1.13.11.51 Details
show Brenda entryEC number
1.13.11.51
Accepted name
9-cis-epoxycarotenoid dioxygenase
Reaction
(1) a 9-cis-epoxycarotenoid + O2 = 2-cis,4-trans-xanthoxin + a 12′-apo-carotenal;;(2) 9-cis-violaxanthin + O2 = 2-cis,4-trans-xanthoxin + (3S,5R,6S)-5,6-epoxy-3-hydroxy-5,6-dihydro-12′-apo-β-caroten-12′-al;;(3) 9′-cis-neoxanthin + O2 = 2-cis,4-trans-xanthoxin + (3S,5R,6R)-5,6-dihydroxy-6,7-didehydro-5,6-dihydro-12′-apo-β-caroten-12′-al
Other name(s)
nine-cis-epoxycarotenoid dioxygenase,
NCED,
AtNCED3,
PvNCED1,
VP14
Systematic name
9-cis-epoxycarotenoid 11,12-dioxygenase
CAS registry number
199877-10-6
Comment
Requires iron(II). Acts on 9-cis-violaxanthin and 9′-cis-neoxanthin but not on the all-trans isomers [2,3]. In vitro, it will cleave 9-cis-zeaxanthin. Catalyses the first step of abscisic-acid biosynthesis from carotenoids in chloroplasts, in response to water stress. The other enzymes involved in the abscisic-acid biosynthesis pathway are EC 1.1.1.288 (xanthoxin dehydrogenase), EC 1.2.3.14 (abscisic-aldehyde oxidase) and EC 1.14.13.93 [(+)-abscisic acid 8′-hydroxylase].
History
created 2005
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1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
1.6.2.1 created 1961, deleted 1965 1.6.2.3 created 1972, deleted 1965 1.13.11.21 created 1972, deleted 2001
