Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2007-1-31
pubmed:abstractText
At1g78500, one of the oxidosqualene cyclase (OSC) homologues from Arabidopsis thaliana, was expressed in a lanosterol synthase-deficient yeast strain and the products were analyzed. In addition to the known triterpenes, this OSC was found to produce two new triterpenes, the structures of which were determined by NMR and MS analyses. The new triterpenes are C-ring-seco-beta-amyrin (1) and C-ring-seco-alpha-amyrin (2) and named beta-seco-amyrin and alpha-seco-amyrin, respectively. beta-seco-Amyrin is produced from the oleanyl cation through bond cleavage between C8 and C14, and alpha-seco-amyrin is produced from the ursanyl cation in the same manner. Together with Grob fragmentation catalyzed by another OSC (marneral synthase) from A. thaliana, the formation of seco-amyrins by this OSC revealed that OSCs not only catalyze carbon-carbon bond formations and Wagner-Meerwein rearrangements but also cleave preformed ring systems in cationic intermediates. Based on this information, direct production of other natural seco-triterpenes by OSCs is proposed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
129
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1450-5
pubmed:dateRevised
2007-5-4
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Origin of structural diversity in natural triterpenes: direct synthesis of seco-triterpene skeletons by oxidosqualene cyclase.
pubmed:affiliation
Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't