EC - Presqualene diphosphate synthase

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IntEnz Enzyme Nomenclature


Accepted name:
presqualene diphosphate synthase
Other names:
SSL-1 (gene name)
hpnD (gene name)
Systematic name:
(2E,6E)-farnesyl-diphosphate:(2E,6E)-farnesyl-diphosphate farnesyltransferase (presqualene diphosphate forming)



Isolated from the green alga Botryococcus braunii BOT22. Unlike EC, squalene synthase, where squalene is formed in one step from farnesyl diphosphate, in this alga the intermediate presqualene diphosphate is generated and released by this enzyme. This compound is then converted into either squalene (by EC, Botryococcus squalene synthase) or botryococcene (EC, botryococcene synthase).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Niehaus, T. D., Okada, S., Devarenne, T. P., Watt, D. S., Sviripa, V., Chappell, J.
    Identification of unique mechanisms for triterpene biosynthesis in Botryococcus braunii.
    Proc. Natl. Acad. Sci. U.S.A. 108 : 12260-12265 (2011). [PMID: 21746901]
  2. Pan, J. J., Solbiati, J. O., Ramamoorthy, G., Hillerich, B. S., Seidel, R. D., Cronan, J. E., Almo, S. C., Poulter, C. D.
    Biosynthesis of Squalene from Farnesyl Diphosphate in Bacteria: Three Steps Catalyzed by Three Enzymes.
    ACS Cent Sci 1 : 77-82 (2015). [PMID: 26258173]

[EC created 2012]