Linked Life Data

17683054

Source:http://linkedlifedata.com/resource/pubmed/id/17683054

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2007-10-10
pubmed:abstractText
The mechanism of the conversion of (E,E)-farnesyl diphosphate (FPP, 1a) to aristolochene (6) catalyzed by aristolochene synthase from Penicillium roqueforti has been proposed to proceed through the neutral intermediate germacrene A (4a). However, much of the experimental evidence is also in agreement with a mechanism in which germacrene A is not an intermediate in the predominant mechanism that leads to the formation of aristolochene, but rather an off-pathway product that is formed in a side reaction. Hence, to elucidate the mechanism of FPP cyclisation the substrate analogue 2-fluoroFPP (1b) was synthesized, and upon incubation with aristolochene synthase was converted to a single pentane extractable product according to GC-MS analysis. On the basis of NMR analyses this product was identified as 2-fluorogermacrene A (4b). Variable temperature (1)H NMR spectroscopy indicated the existence of two conformers of 4b that were in slow exchange at -60 degrees C, while at 90 degrees C the two isomers gave rise to averaged NMR signals. In the major isomer (approximately 75%) the methyl groups on C3 and C7 were most likely in the down-down orientation as had been observed for other (E,E)-germacranes. This work suggests that after an initial concerted cyclisation of FPP to germacryl cation deprotonation leads to the formation of germacrene A, and provides compelling evidence that germacrene A is indeed an on-pathway product of catalysis by aristolochene synthase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1439-4227
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1819-25
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Aristolochene synthase-catalyzed cyclization of 2-fluorofarnesyl-diphosphate to 2-fluorogermacrene A.
pubmed:affiliation
School of Chemistry, Main Building, Cardiff University, Park Place, Cardiff, CF10 3AT, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't