Linked Life Data

15750346

Source:http://linkedlifedata.com/resource/pubmed/id/15750346

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-3-7
pubmed:abstractText
The role of residue C323 in catalysis by human glutamate dehydrogenase isozymes (hGDH1 and hGDH2) was examined by substituting Arg, Gly, Leu, Met, or Tyr at C323 by cassette mutagenesis using synthetic human GDH isozyme genes. As a result, the Km of the enzyme for NADH and alpha-ketoglutarate increased up to 1.6-fold and 1.1-fold, respectively. It seems likely that C323 is not responsible for substrate-binding or coenzyme-binding. The efficiency (kcat/Km) of the mutant enzymes was only 11-14% of that of the wild-type isozymes, mainly due to a decrease in kcat values. There was a linear relationship between incorporation of [14C]p-chloromercuribenzoic acid and loss of enzyme activity that extrapolated to a stoichiometry of one mol of [14C] incorporated per mol of monomer for wild type hGDHs. No incorporation of [14C]p-chloromer-curibenzoic acid was observed with the C323 mutants. ADP and GTP had no effect on the binding of p-chloromercuribenzoic acid, suggesting that C323 is not directly involved in allosteric regulation. There were no differences between the two hGDH isozymes in sensitivities to mutagenesis at C323. Our results suggest that C323 plays an important role in catalysis by human GDH isozymes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1016-8478
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
97-103
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Critical role of the cysteine 323 residue in the catalytic activity of human glutamate dehydrogenase isozymes.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't