KEGG   ENZYME: 1.14.18.10
Entry
EC 1.14.18.10               Enzyme                                 
Name
plant 4,4-dimethylsterol C-4alpha-methyl-monooxygenase;
SMO1 (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-methylidenecycloartanol,ferrocytochrome-b5:oxygen oxidoreductase (C-4alpha-methyl-hydroxylating)
Reaction(IUBMB)
24-methylidenecycloartanol + 6 ferrocytochrome b5 + 3 O2 + 6 H+ = 3beta-hydroxy-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-4alpha-carboxylate + 6 ferricytochrome b5 + 4 H2O (overall reaction) [RN:R12377];
(1a) 24-methylidenecycloartanol + 2 ferrocytochrome b5 + O2 + 2 H+ = 4alpha-(hydroxymethyl)-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol + 2 ferricytochrome b5 + H2O [RN:R12368];
(1b) 4alpha-(hydroxymethyl)-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 4alpha-formyl-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol + 2 ferricytochrome b5 + 2 H2O [RN:R12369];
(1c) 4alpha-formyl-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 3beta-hydroxy-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-4alpha-carboxylate + 2 ferricytochrome b5 + H2O [RN:R12370]
Reaction(KEGG)
Substrate
24-methylidenecycloartanol [CPD:C08830];
ferrocytochrome b5 [CPD:C00999];
O2 [CPD:C00007];
H+ [CPD:C00080];
4alpha-(hydroxymethyl)-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol;
4alpha-formyl-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol
Product
3beta-hydroxy-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-4alpha-carboxylate;
ferricytochrome b5 [CPD:C00996];
H2O [CPD:C00001];
4alpha-(hydroxymethyl)-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol;
4alpha-formyl-4beta,14alpha-dimethyl-9beta,19-cyclo-5alpha-ergost-24(241)-en-3beta-ol
Comment
This plant enzyme catalyses a step in the biosynthesis of sterols. It acts on the 4alpha-methyl group of the 4,4-dimethylated intermediate 24-methylidenecycloartanol 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), which also catalyses the epimerization of the remaining 4beta-methyl into the 4alpha position. Unlike the fungal/animal enzyme EC 1.14.18.9, 4alpha-methylsterol monooxygenase, this enzyme is not able to remove the methyl group from C-4-monomethylated substrates. That activity is performed in plants by a second enzyme, EC 1.14.18.11, plant 4alpha-monomethylsterol monooxygenase.
History
EC 1.14.18.10 created 2019
Pathway
ec00100  Steroid biosynthesis
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K14423  plant 4,4-dimethylsterol C-4alpha-methyl-monooxygenase
Genes
ATHAT4G12110(SMO1-1) AT4G22755 AT4G22756(SMO1-2)
ALY110226378 110226382 9310821
CRB111829641 111829642 17878277 17884650
CSAT104707512 104717801 104718035 104718036 104720179 104722765 104722766 104722767 104731224 104731225 104733374 104737226
EUSEUTSA_v10024722mg EUTSA_v10025849mg EUTSA_v10028846mg
BRP103853483 103860261 103860313
BNA106375731 106375734 106376550 106395025 106440893 106440900
BOE106323132 106323529 106326927
RSZ108819044 108822182 108826950
THJ104813000 104813925
CPAP110817604 110819441
CIT102610279
CICCICLE_v10021364mg
PVY116125412 116128115 116128172
MINC123204022 123210056
TCC18606367 18614230 18614300 18614301 18614438
GRA105763824 105763825 105765153 105792123 105800261
GHI107890661 107896508 107919482 107919503 107926922 107931276 107936415 107945640 107945641 107946958
GAB108457103 108458635 108458637 108468960 108479411
HSYR120192020 120202626 120206712 120213721
DZI111289871 111305927 111306357 111315419
EGR104441851 104443730
GMX100785755 100793153 100793785
GSJ114367510 114393840 114396051 114412109
PVUPHAVU_008G076300g PHAVU_010G081300g
VRA106769322 106779599
VAR108324101 108328655
VUN114179939 114185995
VUM124828945 124846174
CCAJ109802330 109809965
APRC113850460 113852978
MTR11426366 25498869
TPRA123887250
CAM101498049 101499136
PSAT127074119 127127223 127130959
VVO131614309 131637420 131637564
LJALj4g3v1302690.1(Lj4g3v1302690.1)
ADU107471219 107487621
AIP107623619 107630595
AHF112716478 112721686 112783349 112803654
LANG109333400 109350013
PCIN129288105 129311756 129321842
FVE105351403 105352873
RCN112177775 112180715
PPER18778059 18785578
PMUM103331830 103337274 107881149
PAVI110753700 110773748
PDUL117618692 117629198
MDM103420445 103433067
MSYL126620118 126628621
PXB103930498 103938116 103958174 103962383
ZJU107430251 107435696
MNT21405990
CSAV115716028 115716029
CSV101211692
CMO103490939
BHJ120069239
MCHA111020420
CMAX111465081 111498458
CMOS111431186 111448229
CPEP111799947 111809922
RCU107262576 8288054
JCU105643118 105645947
HBR110631783 110645323 110647686 110658049
MESC110600473 110607085
POP18094413 7479230 7488901
PEU105128938 105132225 105132487
PALZ118028552 118036059 118041303
JRE108981850 109011030 118347633
CILL122282858 122289030
CAVE132175610 132176364
QSU111999469
QLO115972153
TWL119980425 120016721
VVI100255536
VRI117905901
SLY101262546 104649012
SPEN107003251 107026679
SOT102605717 102606141
SSTN125845263 125878424
SDUL129886681 129889921
CANN107866563 107873120
LBB132635036 132645703
NTA107798822 107809242 107810865 107828110
NSY104225605 104227542
NTO104085939 104115593
NAU109211816 109214418
INI109147072 109149049 109165996
ITR116015051 116029935 116030447
SIND105155669 105164199 105173233
OEU111366033 111386563 111391303 111398487
EGT105965684
SSPL121744924 121791764 121796398 121800156 121811001
SMIL131025862
APAN127240281 127252576 127255379
HAN110864319 110864321 110864322 110867780
ECAD122585370 122611201
LSV111918756
CCAV112521181 112526832 112527858
DCR108206019 108211255
CSIN114262038 114299562 114311978
RVL131309923 131333476
AEW130752757 130782611 130793079
BVG104892421 104892422
SOE110779099 110784397
CQI110684683 110702588 110719378 110729310 110729358
ATRI130804405
MOF131163729
NNU104611228 104611828
MING122077742 122085506
TSS122648006 122669732
PSOM113275150 113304814 113306673
OSA4331338 4349278
DOSAOs03t0108500-01(Os03g0108500) Os10t0545200-01(Os10g0545200)
OBR102723086
OGL127753258 127768592
BDI100830254 100830279 100832018 100832062
ATS109735447 109742913 109743100 109752552 109759404
TDC119274638 119286504 119294101 119295277 119298075 119298399 119306308 119328285 119338387
TAES123051467 123085710 123086677 123089447 123091300 123096278 123100508 123105854 123107910 123125632 123127385 123161960 123162077 123181575
TUA125506347 125510783 125512642 125525429 125550745
LPER127294147 127297591 127308143
LRD124648424 124671406 124676848 124694335 124699427 124699687 124708784 124708790
SBI8062847 8069599 8071163 8077962
ZMA100217119 100282314
SITA101762442 101770857
SVS117840008 117859214
PVIR120647612 120651800 120673669 120686746 120688009 120691786 120693297 120707052
PHAI112873879 112877714 112882554 112894791 112898047 112902836
PDA103714140 103718600 103720910
EGU105033591 105035357 105042945
MUS103972099 103972632 103985734 103985805 103995011
ZOF121971199 121976464 121980898 121981501 121982993 121984786 121985379 122025017
DCT110101909
PEQ110036326
AOF109837083 109838522
MSIN131248396
NCOL116247288 116262006 116262605 116262607
ATR18441549
SMOSELMODRAFT_104109 SELMODRAFT_170047
PPP112279680 112281769
 » 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
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: 1.14.18.10
IUBMB Enzyme Nomenclature: 1.14.18.10
ExPASy - ENZYME nomenclature database: 1.14.18.10
BRENDA, the Enzyme Database: 1.14.18.10

DBGET integrated database retrieval system