KEGG ENZYME: 1.14.18.11

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

BCOO:

119075284

CCIN:

107273060

OTU:

111419873

PRAP:

110998831

OFU:

114362392

DCI:	103512287 103512289

ATH:	AT1G07420(SMO2-1) AT2G29390(SMO2-2)

ALY:	9315281 9325711

CRB:	17887780 17900058

CSAT:

104700565 104739310 104749943 104754908 104778598 104786746

EUS:	EUTSA_v10008485mg EUTSA_v10017113mg

BRP:	103836444 103843947 103864965

BNA:	106362242 106391117 106402219 106420038 106450049 106450054 111208485

BOE:	106307917 106310476 106336604 106344016

RSZ:	108813689 108819536 108848436 108859993 130506284 130509714

THJ:	104815774 104826306

CPAP:

110812189

CIT:

102611328

CIC:	CICLE_v10029052mg

PVY:

116144931

MINC:

123208340 123224689

TCC:

18590619

GRA:	105782837 105788785

GHI:	107934820 107944828 107950248 107950322

GAB:	108480542 108486460

HSYR:

120142165 120143299 120160068 120162099 120199310

DZI:	111302145 111303661

EGR:

104422462

GMX:	100790183 100816716

GSJ:	114379876 114410260

PVU:	PHAVU_002G074200g PHAVU_002G074300g

VRA:	106755866 106776423

VAR:	108323132 108323139

VUN:	114170147 114173059

VUM:	124827607 124843154

CCAJ:

109801255 109801590

APRC:

113868623 113868923

MTR:	11407532 11410003 120575921 25496266

TPRA:

123895575 123898285 123906764

CAM:	101502074 101515062

PSAT:

127119377

VVO:

131651052

LJA:	130739962 130739964

ADU:	107481295 107488889

AIP:	107631446 107643518

AHF:	112733956 112750064 112791831 112801082

LANG:

109330605 109331516 109332428

PCIN:

129313697 129315857

QSA:	O6P43_000166 O6P43_028181

FVE:

101303960

RCN:

112201412

PPER:

18773152

PMUM:

103321848

PAVI:

110773473

PDUL:

117630888

MDM:	103423556 103447498

MSYL:

126591318 126616813

PXB:	103954259 103964715

ZJU:

107410870

MNT:

21408018

CSAV:

115719554

CSV:	101220009 116403756

CMO:

103497129

BHJ:

120082510

MCHA:

111024686

CMAX:

111469499 111492998

CMOS:

111452253 111464703

CPEP:

111782737 111784635 111785325 111786943 111787435

RCU:

8284099

MEAN:

126688239

HBR:	110636927 110636928 110644392

MESC:

110606641 110619585

POP:	7481517 7485682

PEU:	105131124 105133116

PALZ:

118033002 118058014

PNZ:	133680349 133685824

JRE:	108995763 108998492

CILL:

122292564 122295090

CAVE:

132164527

QSU:

112022554

QLO:

115985585

TWL:	119990517 120015759

VVI:	100242817 100260328

VRI:	117916804 117927889 117932035

SLY:	100736533 101258266

SPEN:

107023487 107023820

SOT:	102589817 102602168

SSTN:

125872604 125872754

SDUL:

129898773 129900827

CANN:

107873488 107875519

LBB:

132605843

NTA:	107784901 107791166 107795609 107803664

NSY:	104232522 104249758

NTO:	104108313 104113382

NAU:	109214178 109227039

INI:	109156240 109157995 109166491

ITR:	116017168 116024961

SIND:

105170642

OEU:	111369663 111374734

EGT:

105957176

SSPL:

121742063 121743358

SMIL:

130991982 131006789

SHIS:

125214484

APAN:

127244331

HAN:	110868287 110873890

ECAD:

122581549 122607629

LSV:	111907260 111907489

CCAV:

112512724 112518020

DCR:	108206447 108206900

CSIN:

114274145 114286899

RVL:	131314156 131316746

AEW:	130761028 130790545

BVG:

104900049

SOE:

110787672

CQI:	110683366 110688354

ATRI:

130814075

MOF:

131147618

NNU:	104597106 104601110

MING:

122058151 122073165

TSS:	122651833 122671597

PSOM:

113298854 113313160

OSA:	4342171 4351226

OBR:	102706395 102708758

OGL:	127755528 127779539

BDI:

100835573

ATS:

109757775

TDC:	119286129 119295701

TAES:

123086313 123091749 123096733

TUA:

125551160

LPER:

127294651

LRD:

124703173

SBI:

8061435

ZMA:	100281761 542766

MFLO:

136449871 136508718 136535752 136540708

SITA:

101758336 101761504

SVS:	117856747 117866461

PVIR:

120645322 120673040 120685455 120707392

PHAI:

112895638 112903000

PDA:	103697377 103715683 103716756

EGU:	105044346 105046366 105052184 105056895

MUS:	103969297 103986994 103991338 103996861

ZOF:	122013056 122015262 122042988 122047500

DCT:

110099264

PEQ:

110021891

AOF:	109822179 109848520

MSIN:

131243823 131252805

NCOL:

116256758

ATR:

18436262

SMO:	SELMODRAFT_151304 SELMODRAFT_173304 SELMODRAFT_231600 SELMODRAFT_233175

PPP:	112285210 112288272

CME:	CYME_CMM277C

GSL:	Gasu_60480

CCP:	CHC_T00010320001

DDI:	DDB_G0279611

DPP:	DICPUDRAFT_28679 DICPUDRAFT_42415 DICPUDRAFT_76018 DICPUDRAFT_80876

DFA:

DFA_11723

ACAN:

ACA1_360510

NGR:	NAEGRDRAFT_61038

PSYC:

DABAL43B_2672

SOK:	D0B54_23595

AGE:	AA314_00718

AVM:	JQX13_12580

MBD:	MEBOL_003525

CFUS:

CYFUS_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

[ath:AT1G07420 AT2G29390]

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