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ENZYME entry: EC 2.5.1.21

Accepted Name
Squalene synthase.
Alternative Name(s)
Farnesyl-diphosphate farnesyltransferase.
Farnesyltransferase.
Presqualene synthase.
Presqualene-diphosphate synthase.
Squalene synthetase.
Reaction catalysed
2 farnesyl diphosphate + NAD(P)H <=> squalene + 2 diphosphate + NAD(P)(+)
Cofactor(s)
Mn(2+) or Mg(2+).
Comment(s)
  • This microsomal enzyme catalyzes the first committed step in the biosynthesis of sterols.
  • In the absence of NAD(P)H, presqualene diphosphate (PSPP) is accumulated.
  • When NAD(P)H is present, presqualene diphosphate does not dissociate from the enzyme during the synthesis of squalene from farnesyl diphosphate (FPP).
  • High concentrations of FPP inhibit the production of squalene but not of PSPP.
Cross-references
PROSITEPDOC00802
BRENDA2.5.1.21
EC2PDB2.5.1.21
ExplorEnz2.5.1.21
PRIAM enzyme-specific profiles2.5.1.21
KEGG Ligand Database for Enzyme Nomenclature2.5.1.21
IUBMB Enzyme Nomenclature2.5.1.21
IntEnz2.5.1.21
MEDLINEFind literature relating to 2.5.1.21
MetaCyc2.5.1.21
UniProtKB/Swiss-Prot
Q9SDW9, BSS_BOTBR;  P53799, FDFT1_ARATH;  Q752X9, FDFT_ASHGO;  
Q32KR6, FDFT_BOVIN;  P78589, FDFT_CANAX;  Q9HGZ6, FDFT_CANGA;  
O74165, FDFT_CYBJA;  Q54DR1, FDFT_DICDI;  P37268, FDFT_HUMAN;  
P53798, FDFT_MOUSE;  Q7S4Z6, FDFT_NEUCR;  P53800, FDFT_NICBE;  
Q5R6U3, FDFT_PONAB;  Q02769, FDFT_RAT;  P36596, FDFT_SCHPO;  
Q92459, FDFT_USTMA;  Q9Y753, FDFT_YARLI;  P29704, FDFT_YEAST;  

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All UniProtKB/Swiss-Prot entries referenced in this entry, with possibility to download in different formats, align etc.
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.5.1.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.5.-.-
All ENZYME / UniProtKB/Swiss-Prot entries corresponding to 2.-.-.-