title: Isomerization of trans-2,delta 5-dienoyl-CoA's to delta 3,delta 5-dienoyl-CoA's in the beta-oxidation of delta 5-unsaturated fatty acids.
abstract: The NADPH-dependent reduction pathway for the metabolism of delta 5-unsaturated fatty acids involves the isomerization of trans-2,delta 5-dienoyl-CoA, initially formed from the dehydrogenation of delta 5-enoyl-CoA, to isomeric delta 3,delta 5-dienoyl-CoA. The latter intermediates were then isomerized to trans-2,trans-4-dienoyl-CoA, which then follows the NADPH-dependent pathway mediated by 2,4-dienoyl-CoA reductase. The isomerization from trans-2,delta 5-dienoyl-CoA to delta 3,delta 5-dienoyl-CoA is catalyzed by delta 3,delta 2-enoyl-CoA isomerase. In this investigation, we identified the stereoisomers of delta 3,delta 5-dienoates that were formed in the reaction. Starting from trans-2,cis-5-decadienoyl-CoA, the isomerization produced cis-3,cis-5- and trans-3,cis-5-decadienoates. On the other hand, trans-2,trans-5-decadienoyl-CoA yielded cis-3,trans-5- and trans-3,trans-5-decadienoates. In addition to purified rat liver delta 3,delta 2-enoyl-CoA isomerase, acyl-CoA oxidase from Arthrobacter also catalyzed the isomerization from trans-2,cis-5-dienoyl-CoA. However, this acyl-CoA oxidase could not catalyze the similar isomerization of trans-2,trans-5-dienoyl-CoA. delta 3,delta 5-t-2,t-4-Dienoyl-CoA isomerase used cis-3,cis-5-, trans-3,cis-5-, and cis-3,trans-5-dienoyl-CoA's as substrates and converted them to trans-2,trans-4-dienoyl-CoA. In contrast, trans-3,trans-5-dienoyl-CoA was not a substrate for this isomerization. Extensive purification of acyl-CoA oxidase through column chromatography could not remove or diminish the isomerization activity associated with acyl-CoA oxidase. Acyl-CoA oxidases derived from Candida and rat liver also possess isomerization activity.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Medical Research Service, Veterans Affairs Medical Center, Cleveland, Ohio 44106.
authors: L S
authors: LS
authors: Chen
authors: S J
authors: SJ
authors: Jin
authors: I
authors: I
authors: Dejak
authors: K Y
authors: KY
authors: Tserng
mesh_terms: D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism*; D042962:Acyl-CoA Oxidase; D000818:Animals; D001173:Arthrobacter / Q000201:enzymology; D002175:Candida / Q000201:enzymology; D019748:Carbon-Carbon Double Bond Isomerases; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D007535:Isomerases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D013237:Stereoisomerism
chemical_list: C091458:5-decenoyl-coenzyme A; D000214:Acyl Coenzyme A; D005227:Fatty Acids; D010088:Oxidoreductases; D042962:Acyl-CoA Oxidase; D007535:Isomerases; D019748:Carbon-Carbon Double Bond Isomerases; C085575:delta(3,5),delta(2,4)-dienoyl-CoA isomerase