Alan Brash
Last active: 3/22/2018

Steric analysis of epoxyalcohol and trihydroxy derivatives of 9-hydroperoxy-linoleic acid from hematin and enzymatic synthesis.

Thomas CP, Boeglin WE, Garcia-Diaz Y, O'Donnell VB, Brash AR
Chem Phys Lipids. 2013 167-168: 21-32

PMID: 23352713 · PMCID: PMC3678760 · DOI:10.1016/j.chemphyslip.2013.01.002

We characterize the allylic epoxyalcohols and their trihydroxy hydrolysis products generated from 9R- and 9S-hydroperoxy-octadecenoic acid (HPODE) under non-enzymatic conditions, reaction with hematin and subsequent acid hydrolysis, and enzymatic conditions, incubation with Beta vulgaris containing a hydroperoxide isomerase and epoxide hydrolase. The products were resolved by HPLC and the regio and stereo-chemistry of the transformations were determined through a combination of (1)H NMR and GC-MS analysis of dimethoxypropane derivatives. Four trihydroxy isomers were identified upon mild acid hydrolysis of 9S,10S-trans-epoxy-11E-13S-hydroxyoctadecenoate: 9S,10R,13S, 9S,12R,13S, 9S,10S,13S and 9S,12S,13S-trihydroxy-octadecenoic acids, in the ratio 40:26:22:12. We also identified a prominent δ-ketol rearrangement product from the hydrolysis as mainly the 9-hydroxy-10E-13-oxo isomer. Short incubation (5 min) of 9R- and 9S-HPODE with B. vulgaris extract yielded the 9R- and 9S-hydroxy-10E-12R,13S-cis-epoxy products respectively. Longer incubation (60 min) gave one specific hydrolysis product via epoxide hydrolase, the 9R/S,12S,13S-trihydroxyoctadecenoate. These studies provide a practical approach for the isolation and characterization of allylic epoxy alcohol and trihydroxy products using a combination of HPLC, GC-MS and (1)H NMR.

Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

MeSH Terms (14)

Beta vulgaris Chromatography, High Pressure Liquid Epoxide Hydrolases Epoxy Compounds Gas Chromatography-Mass Spectrometry Hemin Hydrolysis Intramolecular Oxidoreductases Isomerism Linoleic Acid Magnetic Resonance Spectroscopy Oleic Acids Propanols Stereoisomerism

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