KEGG   ENZYME: 1.14.13.122Help
Entry
EC 1.14.13.122              Enzyme                                 

Name
chlorophyllide-a oxygenase;
chlorophyllide a oxygenase;
chlorophyll-b synthase;
CAO
Class
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor
BRITE hierarchy
Sysname
chlorophyllide-a:oxygen 71-oxidoreductase
Reaction(IUBMB)
chlorophyllide a + 2 O2 + 2 NADPH + 2 H+ = chlorophyllide b + 3 H2O +  NADP+ (overall reaction) [RN:R10080];
(1a) chlorophyllide a + O2 + NADPH + H+ = 71-hydroxychlorophyllide a + H2O + NADP+ [RN:R08203];
(1b) 71-hydroxychlorophyllide a + O2 + NADPH + H+ = chlorophyllide b + 2 H2O + NADP+ [RN:R08204]
Reaction(KEGG)
Substrate
chlorophyllide a [CPD:C02139];
O2 [CPD:C00007];
NADPH [CPD:C00005];
H+ [CPD:C00080];
71-hydroxychlorophyllide a
Product
chlorophyllide b [CPD:C16541];
H2O [CPD:C00001];
NADP+ [CPD:C00006];
71-hydroxychlorophyllide a
Comment
Chlorophyll b is required for the assembly of stable light-harvesting complexes (LHCs) in the chloroplast of green algae, cyanobacteria and plants [2,3]. Contains a mononuclear iron centre [3]. The enzyme catalyses two successive hydroxylations at the 7-methyl group of chlorophyllide a. The second step yields the aldehyde hydrate, which loses H2O spontaneously to form chlorophyllide b [2]. Chlorophyll a and protochlorophyllide a are not substrates [2].
History
EC 1.14.13.122 created 2006 as EC 1.13.12.14, transferred 2011 to EC 1.14.13.122, modified 2011
Pathway
ec00860  Porphyrin and chlorophyll metabolism
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K13600  chlorophyllide a oxygenase
Genes
ATH: AT1G44446(CH1)
ALY: ARALYDRAFT_473812
CSAT: 104742170 104757952 104777569
EUS: EUTSA_v10011377mg
BRP: 103847721
BNA: 106350863 106385836 106415183 111210513
BOE: 106300459 106312441
THJ: 104817365
CPAP: 110813502
CIT: 102606628
TCC: 18592342
EGR: 104450507
VRA: 106780555
VAR: 108338340
CAM: 101515232
ADU: 107459116
AIP: 107609200
LJA: Lj0g3v0362219.1(Lj0g3v0362219.1)
FVE: 101307553
PPER: 18790794
PMUM: 103319820
PAVI: 110750577
PXB: 103940306
CSV: 101205768(CSCAO)
CMO: 103504061
MCHA: 111011875
RCU: 8274070
JCU: 105638943
VVI: 100247245
INI: 109177427
HAN: 110889494
BVG: 104893235
SOE: 110796344
DOSA: Os10t0567100-01(Os10g0567100) Os10t0567400-01(Os10g0567400)
OBR: 102716534
BDI: 100823044
ATS: 109748314(LOC109748314)
SBI: 8077402
ZMA: 100274228 100284976(pco079065e)
SITA: 101772993
PDA: 103702743
EGU: 105037930
DCT: 110096625
AOF: 109825569
ATR: 18436732
MNG: MNEG_8007
MIS: MICPUN_104843(CAO2) MICPUN_56065(CAO1)
APRO: F751_5245
 » show all
Taxonomy
Reference
1  [PMID:10468639]
  Authors
Espineda CE, Linford AS, Devine D, Brusslan JA.
  Title
The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana.
  Journal
Proc. Natl. Acad. Sci. U. S. A. 96 (1999) 10507-11.
  Sequence
[ath:AT1G44446]
Reference
2  [PMID:10758481]
  Authors
Oster U, Tanaka R, Tanaka A, Rudiger W.
  Title
Cloning and functional expression of the gene encoding the key enzyme for chlorophyll b biosynthesis (CAO) from Arabidopsis thaliana.
  Journal
Plant. J. 21 (2000) 305-10.
  Sequence
[ath:AT1G44446]
Reference
3  [PMID:15086960]
  Authors
Eggink LL, LoBrutto R, Brune DC, Brusslan J, Yamasato A, Tanaka A, Hoober JK.
  Title
Synthesis of chlorophyll b: localization of chlorophyllide a oxygenase and discovery of a stable radical in the catalytic subunit.
  Journal
BMC. Plant. Biol. 4 (2004) 5.
  Sequence
Reference
4  [PMID:8307032]
  Authors
Porra RJ, Schafer W, Cmiel E, Katheder I, Scheer H.
  Title
The derivation of the formyl-group oxygen of chlorophyll b in higher plants from molecular oxygen. Achievement of high enrichment of the 7-formyl-group oxygen from 18O2 in greening maize leaves.
  Journal
Eur. J. Biochem. 219 (1994) 671-9.
Other DBs
ExplorEnz - The Enzyme Database: 1.14.13.122
IUBMB Enzyme Nomenclature: 1.14.13.122
ExPASy - ENZYME nomenclature database: 1.14.13.122
BRENDA, the Enzyme Database: 1.14.13.122
CAS: 216503-73-0

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