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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 4 �-Oxidation of ricinoleic acid in plant peroxisome: 7:0, heptanoic acid; 8:0,<br />

octanoic acid; 8:1, octenoic acid; 10:0, decanoic acid; 12:1, dodecenoic acid; 18:1, octadecenoic<br />

acid (oleic acid). (Adapted from Ref. 41.)<br />

hydroxyacyl-CoA is first hydrolyzed by a hydrolase to yield the 2-hydroxy acid. The<br />

2-hydroxy acid is then oxidized by a 2-hydroxy acid oxidase to form 2-oxo-octonoic<br />

acid, which is oxidatively decarboxylated to produce acyl CoA containing one carbon<br />

atom less than the 2-oxo acid. The oxidative decarboxylation allows return to the<br />

acyl-CoA track for further degradation of the parent fatty acid by �-oxidation, without<br />

the requirement of ATP for the renewed activation process [49].<br />

The alternative reaction sequence leading from D-4-hydroxydecanoyl-CoA via<br />

4-oxo-decanoyl-CoA to 2-oxo-octanoate has also been proposed to account for the<br />

presence of 4-oxo-decanoate, which was detected upon ricinoleate catabolism [50].<br />

This in-chain oxidation of hydroxyl groups to oxo groups [51,52] is known as the<br />

biosynthesis of wax components (a process not located in peroxisomes).<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

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