Thiyl radical induced isomerization of unsaturated fatty acids: determination of equilibrium constants

Thiyl radical induced isomerization of unsaturated fatty acids: determination of equilibrium... Thiyl radical-induced isomerization of polyunsaturated fatty acids (PUFAs) have been studied in homogeneous solution and in liposomes. Four one-trans isomers of arachidonic acid have been assigned with the help of 13C NMR spectroscopy. At a dose of 132 Gy, the trans fraction amounts to 9.2 ± 1.2% in each of the four isomers. Therefore, all the four double bonds are equally susceptible to isomerization, which can be achieved by means of gamma radiolysis or chemolysis (AAPH) using both lipophilic and hydrophilic thiols. The equilibrium is characterised by a cis/trans ratio of 19 : 81, far away from the composition of the natural fatty acids (cis fraction 100%). However, compared to the linoleate isomerization in the homogeneous solution, we observed a preferential formation of trans-trans isomers if linoleate is incorporated in the bilayer of liposomes. This difference might be explained by the better fitting of the all-trans isomer into the parallel-aligned acyl chains. The isomerization step takes place within an adduct of the thiyl radical to an olefinic bond. Using a competition method, the numerical value of the equilibrium constant for the adduct formation was determined by pulse radiolysis to be (15 ± 5) dm3 mol-1. This value does not depend on the number of double bonds and holds for all fatty acids under investigation. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Research on Chemical Intermediates Springer Journals

Thiyl radical induced isomerization of unsaturated fatty acids: determination of equilibrium constants

Loading next page...
 
/lp/springer_journal/thiyl-radical-induced-isomerization-of-unsaturated-fatty-acids-vPqb0ONPuA
Publisher
Brill Academic Publishers
Copyright
Copyright © 2001 by VSP
Subject
Chemistry; Inorganic Chemistry; Physical Chemistry; Catalysis
ISSN
0922-6168
eISSN
1568-5675
D.O.I.
10.1163/156856701104202200
Publisher site
See Article on Publisher Site

Abstract

Thiyl radical-induced isomerization of polyunsaturated fatty acids (PUFAs) have been studied in homogeneous solution and in liposomes. Four one-trans isomers of arachidonic acid have been assigned with the help of 13C NMR spectroscopy. At a dose of 132 Gy, the trans fraction amounts to 9.2 ± 1.2% in each of the four isomers. Therefore, all the four double bonds are equally susceptible to isomerization, which can be achieved by means of gamma radiolysis or chemolysis (AAPH) using both lipophilic and hydrophilic thiols. The equilibrium is characterised by a cis/trans ratio of 19 : 81, far away from the composition of the natural fatty acids (cis fraction 100%). However, compared to the linoleate isomerization in the homogeneous solution, we observed a preferential formation of trans-trans isomers if linoleate is incorporated in the bilayer of liposomes. This difference might be explained by the better fitting of the all-trans isomer into the parallel-aligned acyl chains. The isomerization step takes place within an adduct of the thiyl radical to an olefinic bond. Using a competition method, the numerical value of the equilibrium constant for the adduct formation was determined by pulse radiolysis to be (15 ± 5) dm3 mol-1. This value does not depend on the number of double bonds and holds for all fatty acids under investigation.

Journal

Research on Chemical IntermediatesSpringer Journals

Published: Jul 1, 2001

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off