KEGG   ENZYME: 2.5.1.103Help
Entry
EC 2.5.1.103                Enzyme                                 

Name
presqualene diphosphate synthase;
SSL-1 (gene name)
Class
Transferases;
Transferring alkyl or aryl groups, other than methyl groups;
Transferring alkyl or aryl groups, other than methyl groups (only sub-subclass identified to date)
BRITE hierarchy
Sysname
(2E,6E)-farnesyl-diphosphate:(2E,6E)-farnesyl-diphosphate farnesyltransferase (presqualene diphosphate forming)
Reaction(IUBMB)
2 (2E,6E)-farnesyl diphosphate = presqualene diphosphate + diphosphate [RN:R00702]
Reaction(KEGG)
Substrate
(2E,6E)-farnesyl diphosphate [CPD:C00448]
Product
presqualene diphosphate [CPD:C03428];
diphosphate [CPD:C00013]
Comment
Isolated from the green alga Botryococcus braunii BOT22. Unlike EC 2.5.1.21, 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 1.3.1.96, Botryococcus squalene synthase) or botryococcene (EC 1.3.1.97, botryococcene synthase).
History
EC 2.5.1.103 created 2012
Reference
1  [PMID:21746901]
  Authors
Niehaus TD, Okada S, Devarenne TP, Watt DS, Sviripa V, Chappell J
  Title
Identification of unique mechanisms for triterpene biosynthesis in Botryococcus braunii.
  Journal
Proc. Natl. Acad. Sci. U. S. A. 108 (2011) 12260-5.
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 

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