Linked Life Data

12742085

Source:http://linkedlifedata.com/resource/pubmed/id/12742085

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4-5
pubmed:dateCreated
2003-5-13
pubmed:abstractText
In mammalian brain, glutamate dehydrogenase (GDH) is located predominantly in astrocytes, where is thought to play a role in transmitter glutamate's metabolism. Human GDH exists in GLUD1 (housekeeping) and GLUD2 (nerve tissue-specific) isoforms, which share all but 15 out of their 505 amino acids. The GLUD1 GDH is potently inhibited by GTP, whereas the GLUD2 enzyme is resistant to this compound. On the other hand, the GLUD2 isoform assumes in the absence of GTP a conformational state associated with little catalytic activity, but it remains amenable to full activation by ADP and/or L-leucine. Site-directed mutagenesis of the GLUD1 gene at sites that differ from the corresponding residues of the GLUD2 gene showed that replacement of Gly456 by Ala made the enzyme resistant to GTP (IC(50)=2.8+/-0.15 microM) compared to the wild-type GDH (IC(50)=0.19+/-0.01 microM). In addition, substitution of Ser for Arg443 virtually abolished basal activity and rendered the enzyme dependent on ADP for its function. These properties may permit the neural enzyme to be recruited under conditions of low energy charge (high ADP:ATP ratio), similar to those that prevail in synaptic astrocytes during intense glutamatergic transmission. Hence, substitution of Ser for Arg443 and Ala for Gly456 are the main evolutionary changes that led to the adaptation of the GLUD2 GDH to the unique metabolic needs of the nerve tissue.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0197-0186
pubmed:author
pubmed:issnType
Print
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
401-10
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Study of structure-function relationships in human glutamate dehydrogenases reveals novel molecular mechanisms for the regulation of the nerve tissue-specific (GLUD2) isoenzyme.
pubmed:affiliation
Department of Neurology, Section of Medicine, School of Health Sciences, University of Crete, Heraklion, Crete, Greece. plaitak@med.uoc.gr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't