Fatty acid synthesis in mitochondria of Euglena gracilis.
A malonyl-CoA-independent fatty acid synthetic system, different from the systems in other subcellular fractions, occurred in mitochondria of Euglena gracilis. The system had ability to synthesize fatty acids directly from acetyl-CoA as both primer and C2 donor using NADH as an electron donor. Fatty acids were synthesized by reversal of beta-oxidation with the exception that enoyl-CoA reductase functioned instead of acyl-CoA dehydrogenase in degradation system. A fairly high activity of enoyl-CoA reductase was found on various enoyl-CoA substrates (C4-C12) with NADH or NADPH. Three species of enoyl-CoA reductase, distinct from each other by their chain-length specificity, were found in Euglena mitochondria, and one of them was highly specific for crotonyl-CoA. It is also discussed that the mitochondrial fatty-acid synthetic system contributes to wax ester fermentation, the anaerobic energy-generating system found in the organism.
D000105:Acetyl Coenzyme A / Q000378:metabolism; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D044944:Acyl-CoA Dehydrogenases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D005056:Euglena gracilis / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D005227:Fatty Acids / Q000096:biosynthesis*; D007700:Kinetics; D008316:Malonyl Coenzyme A / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D013379:Substrate Specificity
D005227:Fatty Acids; D009243:NAD; D008316:Malonyl Coenzyme A; D009249:NADP; D000105:Acetyl Coenzyme A; D000255:Adenosine Triphosphate; D044944:Acyl-CoA Dehydrogenases; D000103:Acetyl-CoA Carboxylase