KEGG   ENZYME: 1.14.18.9Help
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
BRITE hierarchy
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
ec01130  Biosynthesis of antibiotics
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)
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)
LAV: 100673402
TMU: 101361066
MDO: 100015712(MSMO1)
SHR: 100927294
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)
PADL: 103915840
AAM: 106484071(MSMO1)
ASN: 102373382(MSMO1)
AMJ: 102570191(MSMO1)
PSS: 102449794(MSMO1)
CMY: 102930070(MSMO1)
CPIC: 101942968(MSMO1)
ACS: 100552150(msmo1)
PVT: 110083492(MSMO1)
PMUR: 107290875
PMUA: 114604312
GJA: 107116888(MSMO1)
XLA: 108704957(msmo1.L) 108706637(msmo1.S)
XTR: 780270(msmo1)
NPR: 108788887(MSMO1)
DRE: 406662(msmo1)
SRX: 107750426
SANH: 107655978
SGH: 107548349
CCAR: 109046545
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)
RTP: 109929125
SPU: 582397
APLC: 110977365
SKO: 100377445
DME: Dmel_CG11162(CG11162)
DER: 6551131
DPE: 6602660
AAG: 5567791
PCAN: 112556490
LAK: 106176186
AQU: 100640449
SCE: YGR060W(ERG25)
ERC: Ecym_6269
KMX: KLMA_50284(ERG25)
NCS: NCAS_0A02240(NCAS0A02240)
NDI: NDAI_0D04170(NDAI0D04170)
TPF: TPHA_0B02330(TPHA0B02330)
TBL: TBLA_0D02010(TBLA0D02010)
TDL: TDEL_0E01680(TDEL0E01680)
KAF: KAFR_0F04030(KAFR0F04030)
SPAA: SPAPADRAFT_134612(SUR2.2)
CAL: CAALFM_C401530CA(ERG251) CAALFM_CR02370WA(ERG25)
CTEN: 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
HIR: HETIRDRAFT_148092(smo1)
LBC: LACBIDRAFT_182669(ERG25p-2)
ABP: AGABI1DRAFT115836(AGABI1DRAFT_115836)
ABV: AGABI2DRAFT228680(AGABI2DRAFT_228680)
MGL: MGL_0756
 » show all
Taxonomy
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)
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)
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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