Linked Life Data

11060302

Source:http://linkedlifedata.com/resource/pubmed/id/11060302

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-5-23
pubmed:abstractText
Nitrilases (nitrile aminohydrolases, EC ) are enzymes that catalyze the hydrolysis of nitriles to the corresponding carbon acids. Among the four known nitrilases of Arabidopsis thaliana, the isoform NIT4 is the most divergent one, and homologs of NIT4 are also known from species not belonging to the Brassicaceae like Nicotiana tabacum and Oryza sativa. We expressed A. thaliana NIT4 as hexahistidine tag fusion protein in Escherichia coli. The purified enzyme showed a strong substrate specificity for beta-cyano-l-alanine (Ala(CN)), an intermediate product of cyanide detoxification in higher plants. Interestingly, not only aspartic acid but also asparagine were identified as products of NIT4-catalyzed Ala(CN) hydrolysis. Asn itself was no substrate for NIT4, indicating that it is not an intermediate but one of two reaction products. NIT4 therefore has both nitrilase and nitrile hydratase activity. Several lines of evidence indicate that the catalytic center for both reactions is the same. The NIT4 homologs of N. tabacum were found to catalyze the same reactions and protein extracts of A. thaliana, N. tabacum and Lupinus angustifolius also converted Ala(CN) to Asp and Asn in vitro. NIT4 may play a role in cyanide detoxification during ethylene biosynthesis because extracts from senescent leaves of A. thaliana showed higher Ala(CN) hydratase/nitrilase activities than extracts from nonsenescent tissue.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2616-21
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
The Arabidopsis thaliana isogene NIT4 and its orthologs in tobacco encode beta-cyano-L-alanine hydratase/nitrilase.
pubmed:affiliation
Department of Plant Physiology, Ruhr-Universität, Universitätsstrasse 150, D-44801 Bochum, Germany. Markus.Piotrowski@ruhr-uni-bochum.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't