Linked Life Data

1536925

Source:http://linkedlifedata.com/resource/pubmed/id/1536925

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1992-3-31
pubmed:databankReference
pubmed:abstractText
Chalcone synthase (CHS) and stilbene synthase (STS) are closely related polyketide synthases which are key enzymes in the biosynthesis of flavonoids and stilbenes. Scots pine (Pinus sylvestris) is an interesting plant for a direct comparison of the enzymes. It not only contains the usual flavonoids, but also an unusual chalcone derivative (pinocembrin), and it synthesizes stilbenes of the pinosylvin type. We analysed a CHS and a STS by molecular cloning and functional expression in Escherichia coli. The CHS was active not only with 4-coumaroyl-CoA (to naringenin chalcone), but also with cinnamoyl-CoA (leading to pinocembrin). The STS was identified as dihydropinosylvin synthase, because it preferred dihydrocinnamoyl-CoA to cinnamoyl-CoA. The protein deviated in 47 positions from the CHS consensus. It had 73.2% identity with the CHS from P. sylvestris and only 65.3% with a STS from peanut (Arachis hypogaea). We also investigated the regulation of both enzyme types in P. sylvestris plantlets exposed to stress. CHS was present in non-stressed plantlets, and induction led to a transient increase with a peak after 16 h. STS type activities were regulated differently and were absent in non-stressed plantlets. Increases were observed after a lag period of at least 6 h, and highest activities were obtained after 30 h. The analysis of the reactions in the plant extracts and the substrate specificity of the cloned STS indicate that the plants contain at least two different types of STS: the cloned dihydropinosylvin synthase and a pinosylvin synthase which preferentially utilizes cinnamoyl-CoA as substrate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0167-4412
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
489-503
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Molecular analysis of chalcone and dihydropinosylvin synthase from Scots pine (Pinus sylvestris), and differential regulation of these and related enzyme activities in stressed plants.
pubmed:affiliation
Institut für Biologie II, Biochemie der Pflanzen, Universität Freiburg, FRG.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't