KEGG   ENZYME: 1.14.18.9
Entry
EC 1.14.18.9                Enzyme                                 

Name
4alpha-methylsterol monooxygenase;
methylsterol hydroxylase (ambiguous);
4-methylsterol oxidase (ambiguous);
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol,hydrogen-donor:oxygen oxidoreductase (hydroxylating) (ambiguous);
methylsterol monooxygenase (ambiguous);
ERG25 (gene name);
MSMO1 (gene name);
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol,ferrocytochrome-b5:oxygen oxidoreductase (hydroxylating) (ambiguous)
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
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol,ferrocytochrome-b5:oxygen oxidoreductase (C4alpha-methyl-hydroxylating)
Reaction(IUBMB)
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol + 6 ferrocytochrome b5 + 3 O2 + 6 H+ = 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carboxylate + 6 ferricytochrome b5 + 4 H2O (overall reaction) [RN:R10057];
(1a) 4,4-dimethyl-5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 4alpha-hydroxymethyl-4beta-methyl-5alpha-cholest-7-en-3beta-ol + 2 ferricytochrome b5 + H2O [RN:R04501];
(1b) 4alpha-hydroxymethyl-4beta-methyl-5alpha-cholest-7-en-3beta-ol + 2 ferrocytochrome b5 + O2 + 2 H+ = 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde + 2 ferricytochrome b5 + 2 H2O [RN:R05733];
(1c) 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde + 2 ferrocytochrome b5 + O2 + 2 H+ = 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carboxylate + 2 ferricytochrome b5 + H2O [RN:R05734]
Reaction(KEGG)
Substrate
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol [CPD:C04530];
ferrocytochrome b5 [CPD:C00999];
O2 [CPD:C00007];
H+ [CPD:C00080];
4alpha-hydroxymethyl-4beta-methyl-5alpha-cholest-7-en-3beta-ol [CPD:C04814];
3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde [CPD:C11509]
Product
3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carboxylate [CPD:C04840];
ferricytochrome b5 [CPD:C00996];
H2O [CPD:C00001];
4alpha-hydroxymethyl-4beta-methyl-5alpha-cholest-7-en-3beta-ol [CPD:C04814];
3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde [CPD:C11509]
Comment
This enzyme is found in fungi and animals and catalyses a step in the biosynthesis of important sterol molecules such as ergosterol and cholesterol, respectively. The enzyme acts on the 4alpha-methyl group. Subsequent decarboxylation by EC 1.1.1.170, 3beta-hydroxysteroid-4alpha-carboxylate 3-dehydrogenase (decarboxylating), occurs concomitantly with epimerization of the remaining 4beta-methyl into the 4alpha position, thus making it a suitable substrate for a second round of catalysis. cf. EC 1.14.13.246, 4beta-methylsterol monooxygenase; EC 1.14.18.10, plant 4,4-dimethylsterol C-4alpha-methyl-monooxygenase; and EC 1.14.18.11, plant 4alpha-monomethylsterol monooxygenase.
History
EC 1.14.18.9 created 1972 as EC 1.14.99.16, transferred 2002 to EC 1.14.13.72, transferred 2017 to EC 1.14.18.9, modified 2019
Pathway
ec00100  Steroid biosynthesis
ec01100  Metabolic pathways
ec01110  Biosynthesis of secondary metabolites
Orthology
K07750  methylsterol monooxygenase
Genes
HSA: 6307(MSMO1)
PTR: 738493(MSMO1)
PPS: 100986460(MSMO1)
GGO: 101135163(MSMO1)
PON: 100173838(MSMO1)
NLE: 100603031(MSMO1)
MCC: 705106(MSMO1)
MCF: 101865422(MSMO1)
CSAB: 103236486(MSMO1)
RRO: 104663423(MSMO1)
RBB: 108521935(MSMO1)
CJC: 100398666(MSMO1)
SBQ: 101053419(MSMO1)
MMU: 66234(Msmo1)
MCAL: 110300687(Msmo1)
MPAH: 110336636(Msmo1)
RNO: 140910(Msmo1)
MUN: 110549058(Msmo1)
CGE: 100754784(Msmo1)
NGI: 103732786(Msmo1)
HGL: 101719361(Msmo1)
CCAN: 109687904(Msmo1)
OCU: 100343167(MSMO1)
TUP: 102495765(MSMO1)
CFA: 475491(MSMO1)
VVP: 112916498
AML: 100478610(MSMO1)
UMR: 103658127(MSMO1)
UAH: 113255824(MSMO1)
ORO: 101384837(MSMO1)
ELK: 111154388
FCA: 101096978(MSMO1)
PTG: 102957399(MSMO1)
PPAD: 109262446(MSMO1)
AJU: 106967462(MSMO1)
BTA: 504481(MSMO1)
BOM: 102279364(MSMO1)
BIU: 109571212(MSMO1)
BBUB: 102414195(MSMO1)
CHX: 102180413(MSMO1)
OAS: 101121628(MSMO1)
SSC: 396590(MSMO1)
CFR: 102519347(MSMO1)
CDK: 105087398(MSMO1)
BACU: 103002999(MSMO1)
LVE: 103089686(MSMO1)
OOR: 101289371(MSMO1)
DLE: 111168093(MSMO1)
PCAD: 102973299(MSMO1)
ECB: 100061552(MSMO1)
EPZ: 103567419(MSMO1)
EAI: 106837736(MSMO1)
MYB: 102263681(MSMO1)
MYD: 102755773(MSMO1)
MNA: 107525574(MSMO1)
HAI: 109386939(MSMO1)
DRO: 112312647(MSMO1)
PALE: 102896965(MSMO1)
RAY: 107515609(MSMO1)
MJV: 108394573(MSMO1)
MDO: 100015712(MSMO1)
SHR: 100927294(MSMO1)
PCW: 110200933(MSMO1)
OAA: 100075041(MSMO1)
GGA: 422423(MSMO1)
MGP: 100550538(MSMO1)
CJO: 107313018(MSMO1)
NMEL: 110397908(MSMO1)
APLA: 101804996(MSMO1)
ACYG: 106032325(MSMO1)
TGU: 100222623(MSMO1)
LSR: 110481549(MSMO1)
SCAN: 103825935(MSMO1)
GFR: 102040644(MSMO1)
FAB: 101811763(MSMO1)
PHI: 102111371(MSMO1)
PMAJ: 107203507(MSMO1)
CCAE: 111927886(MSMO1)
CCW: 104690530(MSMO1)
ETL: 114057539(MSMO1)
FPG: 101914205(MSMO1)
FCH: 102050992(MSMO1)
CLV: 102086288(MSMO1)
EGZ: 104124048(MSMO1)
NNI: 104021256(MSMO1)
ACUN: 113479492(MSMO1)
AAM: 106484071(MSMO1)
ASN: 102373382(MSMO1)
AMJ: 102570191(MSMO1)
PSS: 102449794(MSMO1)
CMY: 102930070(MSMO1)
CPIC: 101942968(MSMO1)
ACS: 100552150(msmo1)
PVT: 110083492(MSMO1)
PBI: 103053887
PMUR: 107290875
TSR: 106550763(MSMO1)
GJA: 107116888(MSMO1)
XLA: 108704957(msmo1.L) 108706637(msmo1.S)
XTR: 780270(msmo1)
NPR: 108788887(MSMO1)
DRE: 406662(msmo1)
IPU: 100304913(msmo1)
PHYP: 113544334(msmo1)
AMEX: 103040405(msmo1)
EEE: 113591218(msmo1)
TRU: 101070460(msmo1)
LCO: 104933866(msmo1)
NCC: 104962899
MZE: 101479801(msmo1)
ONL: 100692996(msmo1)
OLA: 105354476(msmo1)
XMA: 102232647(msmo1)
XCO: 114144235(msmo1)
PRET: 103460529(msmo1)
CVG: 107090464(msmo1)
NFU: 107374119(msmo1)
KMR: 108248634(msmo1)
ALIM: 106525846(msmo1)
AOCE: 111574709(msmo1)
CSEM: 103384085(msmo1)
POV: 109638275(msmo1)
LCF: 108893083(msmo1)
SDU: 111216644(msmo1)
SLAL: 111657347(msmo1)
HCQ: 109511157(msmo1)
BPEC: 110167589(msmo1)
MALB: 109972109(msmo1)
SASA: 106590825(msmo1)
ELS: 105008532(msmo1)
SFM: 108924344(msmo1)
PKI: 111837277
LCM: 102357049(MSMO1)
CMK: 103183717(msmo1)
SPU: 582397
APLC: 110977365
SKO: 100377445
PCAN: 112556490
LAK: 106176186
AQU: 100640449
SCE: YGR060W(ERG25)
ERC: Ecym_6269
KMX: KLMA_50284(ERG25)
NCS: NCAS_0A02240(NCAS0A02240) NCAS_0A02420(NCAS0A02420)
NDI: NDAI_0D04170(NDAI0D04170) NDAI_0D04450(NDAI0D04450)
TPF: TPHA_0B02330(TPHA0B02330) TPHA_0F01110(TPHA0F01110)
TBL: TBLA_0D02010(TBLA0D02010)
TDL: TDEL_0E01410(TDEL0E01410) TDEL_0E01680(TDEL0E01680)
KAF: KAFR_0F04030(KAFR0F04030) KAFR_0G03150(KAFR0G03150)
SPAA: SPAPADRAFT_134612(SUR2.2) SPAPADRAFT_62633(ERG25)
CAL: CAALFM_C401530CA(ERG251) CAALFM_CR02370WA(ERG25)
CTEN: CANTEDRAFT_109226(ERG25) CANTEDRAFT_131473(SUR2.2)
SLB: AWJ20_3517(ERG25)
NCR: NCU06402
NTE: NEUTE1DRAFT116421(NEUTE1DRAFT_116421)
SSCK: SPSK_03491
MAW: MAC_06405
MAJ: MAA_05070
CMT: CCM_04265
MBE: MBM_00630
ANG: ANI_1_798034(An03g06410)
PTE: PTT_16124
ZTR: MYCGRDRAFT_36271(ERG25)
SPO: SPAC630.08c(erg25)
CNE: CNC02410
CNB: CNBC4830
TASA: A1Q1_00651
HIR: HETIRDRAFT_148092(smo1)
LBC: LACBIDRAFT_182669(ERG25p-2)
ABP: AGABI1DRAFT115836(AGABI1DRAFT_115836)
ABV: AGABI2DRAFT228680(AGABI2DRAFT_228680)
MRT: MRET_0062
DFA: DFA_04635
SPAR: SPRG_01623
 » show all
Reference
1  [PMID:4383278]
  Authors
Miller WL, Kalafer ME, Gaylor JL, Delwiche CV.
  Title
Investigation of the component reactions of oxidative sterol demethylation. Study of the aerobic and anaerobic processes.
  Journal
Biochemistry 6:2673-8 (1967)
DOI:10.1021/bi00861a005
Reference
2  [PMID:4234469]
  Authors
Gaylor JL, Mason HS.
  Title
Investigation of the component reactions of oxidative sterol demethylation. Evidence against participation of cytochrome P-450.
  Journal
J Biol Chem 243:4966-72 (1968)
Reference
3  [PMID:5791927]
  Authors
Sharpless KB, Snyder TE, Spencer TA, Maheshwari KK, Nelson JA
  Title
Biological demethylation of 4,4-dimethyl sterols, Evidence for enzymic epimerization of the 4beta-methyl group prior to its oxidative removal.
  Journal
J Am Chem Soc 91:3394-6 (1969)
DOI:10.1021/ja01040a065
Reference
4  [PMID:7430141]
  Authors
Brady DR, Crowder RD, Hayes WJ.
  Title
Mixed function oxidases in sterol metabolism. Source of reducing equivalents.
  Journal
J Biol Chem 255:10624-9 (1980)
Reference
5  [PMID:7228857]
  Authors
Fukushima H, Grinstead GF, Gaylor JL.
  Title
Total enzymic synthesis of cholesterol from lanosterol. Cytochrome b5-dependence of 4-methyl sterol oxidase.
  Journal
J Biol Chem 256:4822-6 (1981)
Reference
6  [PMID:3949790]
  Authors
Kawata S, Trzaskos JM, Gaylor JL.
  Title
Affinity chromatography of microsomal enzymes on immobilized detergent-solubilized cytochrome b5.
  Journal
J Biol Chem 261:3790-9 (1986)
Other DBs
ExplorEnz - The Enzyme Database: 1.14.18.9
IUBMB Enzyme Nomenclature: 1.14.18.9
ExPASy - ENZYME nomenclature database: 1.14.18.9
BRENDA, the Enzyme Database: 1.14.18.9
CAS: 37256-80-7

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