KEGG   ENZYME: 1.14.13.122
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
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 metabolism
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K13600  chlorophyllide a oxygenase
Genes
ATHAT1G44446(CH1)
ALY9327352
CRB17900609
CSAT104742170 104757952 104777569
EUSEUTSA_v10011377mg
BRP103847721
BNA106350863 106385836 106415183 111210513
BOE106300459 106312441
RSZ108854699 108863039
THJ104817365
CPAP110813502
CIT102606628
CICCICLE_v10000821mg
PVY116139788
MINC123229567
TCC18592342
GRA105769806 105797165
GHI107905015 107924574
GAB108449929 108476133
DZI111312296 111315638
EGR104450507
GMX100780485 100805998 100806298 100820586
GSJ114382495 114383106 114410418 114415416
PVUPHAVU_008G161000g
VRA106780555
VAR108338340
VUN114194661
CCAJ109808662 109816058
APRC113871002
MTRMTR_1g030480
CAM101515232
LJALj0g3v0362219.1(Lj0g3v0362219.1)
ADU107459116
AIP107609200
AHF112703150 112764943
LANG109328631 109355771 109360317
FVE101307553
RCN112173546
PPER18790794
PMUM103319820
PAVI110750577
PDUL117638843
MDM103431681 103441572
PXB103940306
ZJU107421070 107421073
MNT21408165
CSV101205768
CMO103504061
BHJ120075349
MCHA111011875
CMAX111487368 111489155
CMOS111445103 111462878
CPEP111801911 111808890
RCU8274070
JCU105638943
HBR110640425 110643817
MESC110609367
POP7460954 7466466
PEU105107237 105116314
PALZ118029242 118052508
JRE108981140 108988337
QSU111993681
QLO115960221
TWL119996011 120016258
VVI100247245
VRI117907271
SLY101244441 101261422
SPEN107004538 107023313
SOT102592765 102594460
SSTN125843610 125873766
CANN107868082 107872994 107872996
NTA107770885 107788114 107818187 107824996
NSY104224528 104250169
NTO104116717 104117902
NAU109210030 109212272
INI109177427
ITR116002165
SIND105155361 105159469
OEU111380803 111394351
EGT105974305
SSPL121780178 121805276 121807310
HAN110889494
ECAD122588511
LSV111911963
CCAV112511769
DCR108219296
CSIN114293042
BVG104893235
SOE110796344
CQI110709775 110724618
NNU104587061 104587818
MING122072133 122072788
TSS122667016 122668038
PSOM113346350 113356466
NCOL116246247
OSA4349430 4349433
DOSAOs10t0567100-01(Os10g0567100) Os10t0567400-01(Os10g0567400)
OBR102716534
BDI100823044
ATS109748314
TDC119270600 119278824
TAES123063545 123072674 123080857
TUA125530460
SBI8077402
ZMA100274228 100284976
SITA101772993
SVS117857915
PVIR120644920 120672547 120709320
PHAI112893075
PDA103699659 103702743
EGU105037930
MUS103988166 103989081
DCT110096625
PEQ110035673
AOF109825569
ATR18436732
SMOSELMODRAFT_118803 SELMODRAFT_131716
PPP112274910 112296166
CRECHLRE_01g043350v5
VCNVOLCADRAFT_64158
MNGMNEG_8007
CSLCOCSUDRAFT_18877
CVRCHLNCDRAFT_54799
APROF751_5245
OLUOSTLU_35581 OSTLU_5015
OTAOT_ostta07g02450 OT_ostta12g01390
BPGBathy02g03200 Bathy07g03400
MISMICPUN_104843(CAO2) MICPUN_56065(CAO1)
MPPMICPUCDRAFT_60555(CAO)
ACANACA1_033380
SMINv1.2.031049.t1(symbB.v1.2.031049.t1)
 » show all
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 96:10507-11 (1999)
DOI:10.1073/pnas.96.18.10507
  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 21:305-10 (2000)
DOI:10.1046/j.1365-313x.2000.00672.x
  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 4:5 (2004)
DOI:10.1186/1471-2229-4-5
  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 219:671-9 (1994)
DOI:10.1111/j.1432-1033.1994.tb19983.x
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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