Linked Life Data

21292494

Source:http://linkedlifedata.com/resource/pubmed/id/21292494

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2011-2-14
pubmed:abstractText
Brassinin oxidase, a fungal detoxifying enzyme that mediates the conversion of the phytoalexin brassinin into indole-3-carboxaldehyde, is the first enzyme described to date that catalyzes the transformation of a dithiocarbamate group into an aldehyde equivalent. Brassinin is an essential phytoalexin due to its antifungal activity and its role as biosynthetic precursor of other phytoalexins produced in plants of the family Brassicaceae (common name crucifer). In this report, the isolation, structure determination and synthesis of the elusive co-product of brassinin transformation by brassinin oxidase, S-methyl dithiocarbamate, the syntheses of dideuterated and (R) and (S) monodeuterated brassinins, kinetic analyses of isotope effects and chemical modifications of brassinin oxidase are described. The reaction of [1'-(2)H(2)]brassinin was found to be slowed by a kinetic isotope effect of 5.3 on the value of k(cat)/K(m). This result indicates that the hydride/hydrogen transfer step preceding brassinin transformation is rate determining in the overall reaction. In addition, the use of (R) and (S)-[1'-(2)H]brassinins as substrates indicated that the hydride/hydrogen transfer step is ca. 88% stereoselective for the pro-R hydrogen. A detailed chemical mechanism of the enzymatic transformation of brassinin is proposed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1464-3391
pubmed:author
pubmed:copyrightInfo
Copyright © 2011 Elsevier Ltd. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1390-9
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Brassinin oxidase mediated transformation of the phytoalexin brassinin: structure of the elusive co-product, deuterium isotope effect and stereoselectivity.
pubmed:affiliation
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, Canada S7N 5C9. soledade.pedras@usask.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't