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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1988-6-14
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pubmed:abstractText |
The reaction mechanism for the phosphotriesterase from Pseudomonas diminuta has been examined. When paraoxon (diethyl 4-nitrophenyl phosphate) is hydrolyzed by this enzyme in oxygen-18-labeled water, the oxygen-18 label is found exclusively in the diethyl phosphate product. The absolute configurations for the (+) and (-) enantiomers of O-ethyl phenylphosphonothioic acid have been determined by X-ray diffraction structural determination of the individual crystalline 1-phenylethylamine salts. The (+) enantiomer of the free acid corresponds to the RP configuration. The RP enantiomer of O-ethyl phenylphosphonothioic acid has been converted to the SP enantiomer of EPN [O-ethyl O-(4-nitrophenyl) phenylphosphonothioate]. (SP)-EPN is hydrolyzed by the phosphotriesterase to the SP enantiomer of O-ethyl phenylphosphonothioic acid. The enzymatic reaction therefore proceeds with inversion of configuration. These results have been interpreted as an indication of a single in-line displacement by an activated water molecule directly at the phosphorus center of the phosphotriester substrate. (RP)-EPN is not hydrolyzed by the enzyme at an appreciable rate.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
8
|
pubmed:volume |
27
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pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
1591-7
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading | |
pubmed:year |
1988
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pubmed:articleTitle |
Mechanism and stereochemical course at phosphorus of the reaction catalyzed by a bacterial phosphotriesterase.
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pubmed:affiliation |
Department of Chemistry, Texas A&M University, College Station 77843.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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