| Mechanism and stereochemical course at phosphorus of the reaction catalyzed by a bacterial phosphotriesterase. | |
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MedLine Citation:
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PMID: 2835095 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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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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Authors:
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V E Lewis; W J Donarski; J R Wild; F M Raushel |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Biochemistry Volume: 27 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 1988 Mar |
Date Detail:
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Created Date: 1988-06-14 Completed Date: 1988-06-14 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1591-7 Citation Subset: IM |
Affiliation:
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Department of Chemistry, Texas A&M University, College Station 77843. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Chemical Phenomena Chemistry Organothiophosphorus Compounds / metabolism* Phosphoric Monoester Hydrolases / metabolism* Pseudomonas / enzymology* Stereoisomerism |
| Grant Support | |
ID/Acronym/Agency:
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DK-01366/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Organothiophosphorus Compounds; EC 3.1.3.-/Phosphoric Monoester Hydrolases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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