Linked Life Data

1918058

Source:http://linkedlifedata.com/resource/pubmed/id/1918058

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
1991-11-14
pubmed:abstractText
To test the proposition that a histidine residue is essential in the catalytic mechanism of glutathione S-transferase, rat liver isoenzyme 3-3 specifically labeled with [ring-2-13C]histidine was prepared. The 13C NMR spectrum of the labeled enzyme revealed four resonances corresponding to the 4 histidine residues in the mu gene class type 3 subunit. Titration of the four resonances in the range of pH 4-9 both in the presence and absence of glutathione gave pK alpha values of much less than 4, 5.2, 7.1, and 7.8 for the four side chains that were identified by site-specific mutagenesis as His14, His83, His84, and His167, respectively. The magnetic resonance properties and titration behavior of His14 suggest that this residue is buried in a hydrophobic environment. Conservative replacement of each histidine with asparagine results in mutant enzymes that have catalytic properties very close to the native protein as assessed with three different substrates, 1-chloro-2,4-dinitrobenzene, 4-phenyl-3-buten-2-one, and phenanthrene 9,10-oxide. The results indicate clearly that none of the histidine residues of isoenzyme 3-3 is essential for stabilization of the bound glutathione thiolate or for any other aspect of catalysis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19475-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Are the histidine residues of glutathione S-transferase important in catalysis? An assessment by 13C NMR spectroscopy and site-specific mutagenesis.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of Maryland, College Park 20742.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.