Peroxisomal beta-oxidation is a significant pathway for catabolism of fatty acids in a marine teleost.
Hepatic beta-oxidation is characterized in a marine teleost, Myoxocephalus octodecimspinosus, to determine mitochondrial and peroxisomal substrate selectivity as well as metabolic partitioning. Substrate selectivity is broad for peroxisomal beta-oxidation. Acyl CoA oxidase activities, with all unsaturated substrates measured, are at least 35% of activity with palmitoyl CoA (16:0), a saturated substrate. Mitochondrial selectivities are more pronounced. Carnitine palmitoyltransferase activity with a monounsaturate, palmitoleoyl CoA (16:1), is nearly 40% greater than activity with palmitoyl CoA, whereas activities with two polyunsaturates are < 10% of activity with the saturate. The presence of polyunsaturated acyl CoA esters inhibits up to 70% the oxidation of palmitoyl CoA by intact peroxisomes. Acyl CoA hydrolase activity is localized to peroxisomal fractions prepared by density-gradient centrifugation. Hydrolytic activity in these fractions is nearly twofold the activity of beta-oxidation. Estimates for metabolic partitioning suggest that at least 50% of hepatic beta-oxidation may be initiated by the peroxisomal compartment.
Crockett
E L
EL
Department of Zoology, University of Maine, Orono 04469.
Sidell
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BD
D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008830:Microbodies / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D010084:Oxidation-Reduction; D010171:Palmitoyl Coenzyme A / Q000378:metabolism; D010170:Palmitoyl-CoA Hydrolase / Q000378:metabolism; D013379:Substrate Specificity
D005227:Fatty Acids; D010171:Palmitoyl Coenzyme A; D002334:Carnitine O-Palmitoyltransferase; D010170:Palmitoyl-CoA Hydrolase