Beta-oxidation of unsaturated fatty acids in rat heart mitochondria and Escherichia coli.
Item
-
Title
-
Beta-oxidation of unsaturated fatty acids in rat heart mitochondria and Escherichia coli.
-
Identifier
-
AAI3144134
-
identifier
-
3144134
-
Creator
-
Ren, Ying.
-
Contributor
-
Adviser: Horst Schulz
-
Date
-
2004
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Chemistry, Biochemistry
-
Abstract
-
Unsaturated fatty acids with odd-numbered double bonds, e.g. oleic acid, can be degraded by beta-oxidation via the isomerase-dependent pathway or reductase-dependent pathway. The degradation of 2-trans,5- cis-tetradecadienoyl-CoA, a metabolite of oleic acid, was studied with rat heart mitochondria. It is concluded that both pathways are essential for the degradation of unsaturated fatty acids with odd-numbered double bonds inasmuch as the isomerase-dependent pathway facilitates the major flux through beta-oxidation and the reductase-dependent pathway prevents the accumulation of 3,5- cis-tetradecadienoyl-CoA, an otherwise undegradable metabolite.;This study relied on the use of a mitochondrial extract that permitted the analysis of intermediates but did not maintain the supramolecular organization of enzymes as they exist in intact mitochondria. The use of an organized beta-oxidation system uncompromised by its isolation as present in E. coli would be advantageous. Data obtained with the E. coli fatty acid oxidation complex prompt the conclusion that oleate is mostly degraded via the isomerase-dependent pathway, but that a small amount of 2- trans,5-cis-tetradecadienoyl-CoA is diverted from that pathway via conversion to 3,5-cis-tetradecadienoyl-CoA by Delta3, Delta2-enoyl-CoA isomerase. The 3,5-intermediate, which would strongly inhibit beta-oxidation of oleate, is hydrolyzed and the resultant 3,5-tetradecadienoate is excreted into the growth medium. The substrate profile and kinetic data of the purified recombinant E. coli thioesterase II support the conclusion that this enzyme is responsible for hydrolyzing 3,5-cis-tetradecadienoyl-CoA.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
