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Pathway Description
Fatty Acid Elongation in Mitochondria
Bos taurus
Category:
Metabolite Pathway
Sub-Category:
Metabolic
Created: 2018-08-10
Last Updated: 2019-08-16
Cells typically contain large amounts of C18 and C20 fatty acids. Longer chain fatty acids are found in certain specialized tissues (myelin contains high amounts of C22 and C24 components). Even longer chain fatty acids are derived from either dietary sources or from elongation of C16-CoA or C18-CoA formed by the cytoplasmic fatty acid synthetase system. All of the fatty acids needed by the body can be synthesized from palmitate (C16:0) except the essential, polyunsaturated fatty acids such as linoleate and linolenate. To create longer, shorter, oxidized, reduced fatty acids, palmitic acid is subjected to enzymatic reactions by reductases, hydroxylases, elongases and mixed function oxidases. There are 3 major processes that modify palmitic acid: elongation, desaturation and hydroxylation. Elongation of fatty acids may occur at endoplasmic reticulum where fatty acid molecules of length up to C24 may be produced. Mitochondrial elongation may result in fatty acids up to C16 in length. Fatty acid elongation in mitochondria is essentially the reverse of beta-oxidation for fatty acid oxidation. In particular, both pathways make use of acetyl-CoA acyltransferase, 3-hydroxyacyl-CoA dehydrogenase and enoyl-CoA hydratase. The final step of fatty acid elongation uses enoyl-CoA reductase (not part of the beta-oxidation pathway). The elongation takes place in the mitochondrial matrix. In liver and kidney fatty acid elongation operates best in the presence of both NADH and NADPH, whereas in heart and skeletal muscle, only NADH is required. The mitochondrial pathway is important for elongating fatty acids containing 14 or fewer carbon atoms. Short chain fatty acids (SCFA) are fatty acids with aliphatic tails of less than six carbons. Medium chain fatty acids (MCFA) are fatty acids with aliphatic tails of 612 carbons. Long chain fatty acids (LCFA) are fatty acids with aliphatic tails longer than 12 carbons. Very Long chain fatty acids (VLCFA) are fatty acids with aliphatic tails longer than 22 carbons.
References
Fatty Acid Elongation in Mitochondria References
Furuta S, Kobayashi A, Miyazawa S, Hashimoto T: Cloning and expression of cDNA for a newly identified isozyme of bovine liver 3-hydroxyacyl-CoA dehydrogenase and its import into mitochondria. Biochim Biophys Acta. 1997 Feb 28;1350(3):317-24. doi: 10.1016/s0167-4781(96)00171-6.
Pubmed: 9061028
Zimin AV, Delcher AL, Florea L, Kelley DR, Schatz MC, Puiu D, Hanrahan F, Pertea G, Van Tassell CP, Sonstegard TS, Marcais G, Roberts M, Subramanian P, Yorke JA, Salzberg SL: A whole-genome assembly of the domestic cow, Bos taurus. Genome Biol. 2009;10(4):R42. doi: 10.1186/gb-2009-10-4-r42. Epub 2009 Apr 24.
Pubmed: 19393038
Harhay GP, Sonstegard TS, Keele JW, Heaton MP, Clawson ML, Snelling WM, Wiedmann RT, Van Tassell CP, Smith TP: Characterization of 954 bovine full-CDS cDNA sequences. BMC Genomics. 2005 Nov 23;6:166. doi: 10.1186/1471-2164-6-166.
Pubmed: 16305752
Miinalainen IJ, Chen ZJ, Torkko JM, Pirila PL, Sormunen RT, Bergmann U, Qin YM, Hiltunen JK: Characterization of 2-enoyl thioester reductase from mammals. An ortholog of YBR026p/MRF1'p of the yeast mitochondrial fatty acid synthesis type II. J Biol Chem. 2003 May 30;278(22):20154-61. doi: 10.1074/jbc.M302851200. Epub 2003 Mar 24.
Pubmed: 12654921
This pathway was propagated using PathWhiz -
Pon, A. et al. Pathways with PathWhiz (2015) Nucleic Acids Res. 43(Web Server issue): W552–W559.
Propagated from SMP0000054
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