KEGG   ENZYME: 1.14.18.11
Entry
EC 1.14.18.11               Enzyme                                 
Name
plant 4alpha-monomethylsterol monooxygenase;
SMO2 (gene name)
Class
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With another compound as one donor, and incorporation of one atom of oxygen into the other donor
Sysname
24-ethylidenelophenol,ferrocytochrome-b5:oxygen oxidoreductase (C-4alpha-methyl-hydroxylating)
Reaction(IUBMB)
24-methylidenelophenol + 6 ferrocytochrome b5 + 3 O2 + 6 H+ = 3beta-hydroxyergosta-7,24(241)-dien-4alpha-carboxylate + 6 ferricytochrome b5 + 4 H2O (overall reaction) [RN:R12378];
(1a) 24-methylidenelophenol + 2 ferrocytochrome b5 + O2 + 2 H+ = 4alpha-(hydroxymethyl)ergosta-7,24(241)-dien-3beta-ol + 2 ferricytochrome b5 + H2O [RN:R12372];
(1b) 4alpha-(hydroxymethyl)ergosta-7,24(241)-dien-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 4alpha-formylergosta-7,24(241)-dien-3beta-ol + 2 ferricytochrome b5 + 2 H2O [RN:R12373];
(1c) 4alpha-formylergosta-7,24(241)-dien-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 3beta-hydroxyergosta-7,24(241)-dien-4alpha-carboxylate + 2 ferricytochrome b5 + H2O [RN:R12374]
Reaction(KEGG)
R12372 R12373 R12374 R12378;
(other) R12379
Substrate
24-methylidenelophenol [CPD:C11522];
ferrocytochrome b5 [CPD:C00999];
O2 [CPD:C00007];
H+ [CPD:C00080];
4alpha-(hydroxymethyl)ergosta-7,24(241)-dien-3beta-ol;
4alpha-formylergosta-7,24(241)-dien-3beta-ol
Product
3beta-hydroxyergosta-7,24(241)-dien-4alpha-carboxylate;
ferricytochrome b5 [CPD:C00996];
H2O [CPD:C00001];
4alpha-(hydroxymethyl)ergosta-7,24(241)-dien-3beta-ol;
4alpha-formylergosta-7,24(241)-dien-3beta-ol
Comment
This plant enzyme catalyses a step in the biosynthesis of sterols. It acts on the methyl group of the 4alpha-methylated intermediates 24-ethylidenelophenol and 24-methylidenelophenol and catalyses three successive oxidations, turning it into a carboxyl group. The carboxylate is subsequently removed by EC 1.1.1.418, plant 3beta-hydroxysteroid-4alpha-carboxylate 3-dehydrogenase (decarboxylating). Unlike the fungal/animal enzyme EC 1.14.18.9, 4alpha-methylsterol monooxygenase, this enzyme is not able to act on 4,4-dimethylated substrates. That activity, which occurs earlier in the pathway, is performed in plants by a second enzyme, EC 1.14.18.10, plant 4,4-dimethylsterol C-4alpha-methyl-monooxygenase.
History
EC 1.14.18.11 created 2019
Pathway
ec00100  Steroid biosynthesis
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K14424  plant 4alpha-monomethylsterol monooxygenase
Genes
BCOO119075284
CCIN107273060
OTU111419873
PRAP110998831
OFU114362392
DCI103512287 103512289
ATHAT1G07420(SMO2-1) AT2G29390(SMO2-2)
ALY9315281 9325711
CRB17887780 17900058
CSAT104700565 104739310 104749943 104754908 104778598 104786746
EUSEUTSA_v10008485mg EUTSA_v10017113mg
BRP103836444 103843947 103864965
BNA106362242 106362243 106391117 106402219 106420038 106450049 106450054 106453376 111208485
BOE106307917 106310476 106336604 106344016
RSZ108813689 108819536 108848436 108851590 108859993
THJ104815774 104826306
CPAP110812189
CIT102611328
CICCICLE_v10029052mg
PVY116144931
MINC123208340 123224689
TCC18590619
GRA105782837 105788785
GHI107934820 107944828 107950248 107950322
GAB108480542 108486460
DZI111302145 111303661
EGR104422462
GMX100790183 100816716
GSJ114379876 114410260
PVUPHAVU_002G074200g PHAVU_002G074300g
VRA106755866 106776423
VAR108323132 108323139
VUN114170147 114173059
CCAJ109801255 109801590
APRC113868623 113868923
MTR11407532 11410003 120575921 25496266
CAM101502074 101515062
PSAT127119377
LJALj2g3v1375540.1(Lj2g3v1375540.1)
ADU107481295 107488889
AIP107631446 107643518
AHF112733956 112750064 112791831 112801082
LANG109330605 109331516 109332428
FVE101303960
RCN112201412
PPER18773152
PMUM103321848
PAVI110773473
PDUL117630888
MDM103423556 103447498
PXB103954259 103964715
ZJU107410870
MNT21408018
CSV101220009 116403756
CMO103497129
BHJ120082510
MCHA111024686
CMAX111469499 111492998
CMOS111452253 111464703
CPEP111782737 111784635 111785325 111786943 111787435
RCU8284099
HBR110636927 110636928 110644392
MESC110606641 110619585
POP7481517 7485682
PEU105131124 105133116
PALZ118033002 118058014
JRE108995763 108998492
QSU112022554 112026279
QLO115985585
TWL119990517 120015759
VVI100242817 100260328
VRI117916804 117927889 117932035
SLY100736533 101258266
SPEN107023487 107023820
SOT102589817 102602168
SSTN125872604 125872754
CANN107873488 107875519
NTA107784901 107791166 107795609 107803664
NSY104232522 104249758
NTO104108313 104113382
NAU109214178 109227039
INI109156240 109157995 109166491
ITR116017168 116024961
SIND105170642
OEU111369663 111374734
EGT105957176
SSPL121742063 121743358
HAN110868287 110873890
ECAD122581549 122607629
LSV111907260 111907489
CCAV112512724 112518020
DCR108206447 108206900
CSIN114274145 114286899
BVG104900049
SOE110787672
CQI110683366 110688354
NNU104597106 104601110
MING122058151 122073165
TSS122651833 122671597
PSOM113298854 113313160
NCOL116256758
OSA4342171 4351226
DOSAOs07t0101500-01(Os07g0101500) Os11t0707600-01(Os11g0707600)
OBR102706395 102708758
BDI100835573
ATS109757775
TDC119286129 119295701
TAES123086313 123091749 123096733
TUA125551160
SBI8061435
ZMA100281761 542766
SITA101758336 101761504
SVS117856747 117866461
PVIR120645322 120673040 120685455 120707392
PHAI112895638 112903000
PDA103697377 103715683 103716756
EGU105044346 105046366 105052184 105056895
MUS103969297 103986994 103991338 103996861
DCT110099264
PEQ110021891
AOF109822179 109848520
ATR18436262
SMOSELMODRAFT_151304 SELMODRAFT_173304 SELMODRAFT_231600 SELMODRAFT_233175
PPP112285210 112288272
CMECYME_CMM277C
GSLGasu_60480
CCPCHC_T00010320001
DDIDDB_G0279611
DPPDICPUDRAFT_28679 DICPUDRAFT_42415 DICPUDRAFT_76018 DICPUDRAFT_80876
DFADFA_11723
ACANACA1_360510
NGRNAEGRDRAFT_61038
PSYCDABAL43B_2672
SOKD0B54_23595
AGEAA314_00718
AVMJQX13_12580
MBDMEBOL_003525
CFUSCYFUS_000150
 » show all
Reference
1  [PMID:8505296]
  Authors
Pascal S, Taton M, Rahier A
  Title
Plant sterol biosynthesis. Identification and characterization of two distinct microsomal oxidative enzymatic systems involved in sterol C4-demethylation.
  Journal
J Biol Chem 268:11639-54 (1993)
Reference
2  [PMID:9240456]
  Authors
Rahier A, Smith M, Taton M.
  Title
The role of cytochrome b5 in 4alpha-methyl-oxidation and C5(6) desaturation of plant sterol precursors.
  Journal
Biochem Biophys Res Commun 236:434-7 (1997)
DOI:10.1006/bbrc.1997.6974
Reference
3  [PMID:11707264]
  Authors
Darnet S, Bard M, Rahier A
  Title
Functional identification of sterol-4alpha-methyl oxidase cDNAs from Arabidopsis thaliana by complementation of a yeast erg25 mutant lacking sterol-4alpha-methyl oxidation.
  Journal
FEBS Lett 508:39-43 (2001)
DOI:10.1016/S0014-5793(01)03002-2
  Sequence
Reference
4  [PMID:14653780]
  Authors
Darnet S, Rahier A
  Title
Plant sterol biosynthesis: identification of two distinct families of sterol 4alpha-methyl oxidases.
  Journal
Biochem J 378:889-98 (2004)
DOI:10.1042/BJ20031572
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 1.14.18.11
IUBMB Enzyme Nomenclature: 1.14.18.11
ExPASy - ENZYME nomenclature database: 1.14.18.11
BRENDA, the Enzyme Database: 1.14.18.11

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