Linked Life Data

11525507

Source:http://linkedlifedata.com/resource/pubmed/id/11525507

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-8-29
pubmed:abstractText
Three of the nitrilase isoenzymes of Arabidopsis thaliana (L.) Heynh. are located on chromosome III in tandem and these genes (NIT2/NIT1/NIT3 in the 5'-->3' direction) encode highly similar polypeptides. Copy DNAs encompassing the entire coding sequences for all three nitrilases were expressed in Escherichia coli as fusion proteins containing a C-terminal hexahistidine extension. All three nitrilases were obtained as enzymatically active proteins, and their characteristics were determined, including a detailed comparative analysis of their substrate preferences. All three nitrilases converted indole-3-acetonitrile (IAN) to indole-3-acetic acid (IAA), albeit, compared to the most effective substrates found, phenylpropionitrile (PPN), allylcyanide, (phenylthio)acetonitrile and (methylthio)acetonitrile, with low affinity and velocity. The preferred substrates are either naturally occurring substrates, which may originate from glucosinolate breakdown, or they are close relatives of these. Thus, a major function of NIT1, NIT2 and NIT3 is assigned to be the conversion to carboxylic acids of nitriles from glucosinolate turnover or degradation. While all nitrilases exhibit a similar pH optimum around neutral, and NIT1 and NIT3 exhibit a similar temperature optimum around 30 degrees C independent of the substrate analyzed (IAN, PPN), NIT2 showed a remarkably different temperature optimum for IAN (15 degrees C) and PPN (35-40 degrees C). A potential role for NIT2 in breaking seed dormancy in A. thaliana by low temperatures (stratification), however, was ruled out, although NIT2 was the predominantly expressed nitrilase isoform in developing embryos and in germinating seeds, as judged from an analysis of beta-glucuronidase reporter gene expression under the control of the promoters of the four isogenes. It is possible that NIT2 is involved in supplying IAA during seed development rather than during stratification.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0032-0935
pubmed:author
pubmed:issnType
Print
pubmed:volume
212
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
508-16
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:11525507-Aminohydrolases, pubmed-meshheading:11525507-Arabidopsis, pubmed-meshheading:11525507-Arabidopsis Proteins, pubmed-meshheading:11525507-Base Sequence, pubmed-meshheading:11525507-Cloning, Molecular, pubmed-meshheading:11525507-Gene Expression Regulation, Plant, pubmed-meshheading:11525507-Germination, pubmed-meshheading:11525507-Glucuronidase, pubmed-meshheading:11525507-Hydro-Lyases, pubmed-meshheading:11525507-Hydrogen-Ion Concentration, pubmed-meshheading:11525507-Indoleacetic Acids, pubmed-meshheading:11525507-Isoenzymes, pubmed-meshheading:11525507-Molecular Sequence Data, pubmed-meshheading:11525507-Multigene Family, pubmed-meshheading:11525507-Mutation, pubmed-meshheading:11525507-Plant Growth Regulators, pubmed-meshheading:11525507-Plants, Genetically Modified, pubmed-meshheading:11525507-Promoter Regions, Genetic, pubmed-meshheading:11525507-Seeds, pubmed-meshheading:11525507-Substrate Specificity, pubmed-meshheading:11525507-Temperature
pubmed:year
2001
pubmed:articleTitle
Enzymatic characterization of the recombinant Arabidopsis thaliana nitrilase subfamily encoded by the NIT2/NIT1/NIT3-gene cluster.
pubmed:affiliation
Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität, Bochum, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't