Linked Life Data

8931562

Source:http://linkedlifedata.com/resource/pubmed/id/8931562

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
1997-1-7
pubmed:databankReference
pubmed:abstractText
Tetrachlorohydroquinone dehalogenase is found in Sphingomonas chlorophenolica, a soil bacterium that degrades pentachlorophenol, a widely used wood preservative. This enzyme converts tetrachlorohydroquinone (TCHQ) to trichlorohydroquinone (TriCHQ) and TriCHQ to dichlorohydroquinone (DCHQ) (Xun et al. (1992) J. Bacteriol. 174, 8003-8007). The reducing equivalents for each step are provided by two molecules of glutathione (Xun et al. (1992) Biochem. Biophys. Res. Commun. 182, 361-366). In addition to the expected TriCHQ and DCHQ products, the enzyme also produces substantial amounts of 2,3,5-trichloro-6-S-glutathionylhydroquinone (GS-TriCHQ) and an unidentified isomer of dichloro-S-glutathionylhydroquinone (GS-DCHQ). Treatment of the purified enzyme with dithiothreitol dramatically decreases the formation of GS-TriCHQ and GS-DCHQ. Furthermore, enzyme in freshly-prepared crude extracts forms only very small amounts of GS-TriCHQ and GS-DCHQ. We conclude that GS-TriCHQ and GS-DCHQ are produced by enzyme that has undergone some type of oxidative damage and are therefore not physiologically relevant products. The fact that the oxidative damage can be repaired by DTT suggests that a cysteine or methionine residue may be involved. We have created the C13S and C156S mutants of the enzyme. The C13S mutant converts TCHQ to GS-TriCHQ and GS-DCHQ, rather than to DCHQ. Thus, Cys13 is required for the reductive dehalogenation of TCHQ. A mechanism for the reaction which involves Cys13 is proposed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14634-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Exploration of the relationship between tetrachlorohydroquinone dehalogenase and the glutathione S-transferase superfamily.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of Colorado at Boulder 80309, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't