Document Detail

Mouse serum paraoxonase-1 lactonase activity is specific for medium-chain length fatty acid lactones.
MedLine Citation:
PMID:  21044894     Owner:  NLM     Status:  In-Process    
Recent studies suggest that paraoxonase-1 (PON1), complexed with high-density lipoproteins, is the major lactonase in the circulation. Using 5-hydroxy eicosatetraenoate δ-lactone (5-HETEL) as the substrate, we observed lactonase activity in serum from Pon1-/- mice. However, 6-12 carbon fatty acid γ- and δ-lactones were not hydrolyzed in serum from Pon1-/- mice. Serum from both wild-type and Pon1-/- mice contained a lactonase activity towards 5-HETEL and 3-oxo-dodecanoyl-homoserine lactone that was resistant to inactivation by EDTA. This lactonase activity was sensitive to the serine esterase inhibitor phenyl methyl sulfonyl fluoride and co-eluted with carboxylesterase activity by size-exclusion chromatography. Analysis of serum from the Es1e mouse strain, which has a deficiency in the carboxylesterase, ES-1, proved that this activity was due to ES-1. PON1 activity predominated at early time points (30 s), whereas both PON1 and ES-1 contributed equally at later time points (15 min). When both PON1 and ES-1 were inhibited, 5-HETEL was stable in mouse serum. Thus, while long-chain fatty acid lactones are substrates for PON1, they can be hydrolyzed by ES-1 at neutral pH. In contrast, medium-chain length fatty acid lactones are stable in mouse serum in the absence of PON1, suggesting that PON1 plays a specific role in the metabolism of these compounds.
Philip W Connelly; Clive M Picardo; Philip M Potter; John F Teiber; Graham F Maguire; Dominic S Ng
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-29
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1811     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-12-06     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  39-45     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier B.V. All rights reserved.
Department of Medicine, University of Toronto, Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
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