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Pathway Description
Fatty Acid Biosynthesis
Homo sapiens
Metabolic Pathway
Created: 2013-08-19
Last Updated: 2023-10-25
The biosynthesis of fatty acids primarily occurs in liver and lactating mammary glands. The entire synthesis process which produces palmitic acid occurs on a multifunctional dimeric protein Fatty Acid Synthase (FA) in the cytosol. The production of palmitic acid can be summarized as the successive addition of two carbons to an initial acetyl moiety primer. After 7 cycles palimitic acid is released. The synthesis starts with the sequential transfer of a primer substrate, acetyl-CoA, to the nucleophilic serine residue of the acyltransferase domain of FA. The acetyl moiety is then transferred to the Acyl Carrier Protein (ACP) domain of FA, then finally to the active site of the beta-ketoacyl synthase domain. A chain extender substrate, molonyl-CoA, is transferred to the nucleophilic serine residue of the acyltransferase domain and subsequently to the ACP domain. The acetyl moiety is extend by a condensation reaction, catalysed by the beta-ketoacyl synthase domain, that produces a new Carbon-Carbon bound, this reaction is coupled to a decarboxylation resulting in the production of carbon dioxide. Subsequently beta-ketoacyl condensation product is reduced to a saturated acyl moiety through the step wise action on the beta-ketoacyl reductase, beta-hydroxyacyl dehydrase and enoyl reductase domains respectively. This saturated acyl moiety is then transfer back to the active site of the beta-ketoacyl synthase domain, another molonyl-CoA is loaded and the process repeats. The addition of molonyl moieties occurs 7 times after which the final product is released by that action of thioesterase domain. The final product is 16 carbon long palmitic acid.
References
Fatty Acid Biosynthesis References
Lehninger, A.L. Lehninger principles of biochemistry (4th ed.) (2005). New York: W.H Freeman.
Vance, D.E., and Vance, J.E. Biochemistry of lipids, lipoproteins, and membranes (5th ed.) (2008) Amsterdam; Boston: Elsevier.
Smith S, Witkowski A, Joshi AK: Structural and functional organization of the animal fatty acid synthase. Prog Lipid Res. 2003 Jul;42(4):289-317.
Pubmed: 12689621
Abu-Elheiga L, Jayakumar A, Baldini A, Chirala SS, Wakil SJ: Human acetyl-CoA carboxylase: characterization, molecular cloning, and evidence for two isoforms. Proc Natl Acad Sci U S A. 1995 Apr 25;92(9):4011-5. doi: 10.1073/pnas.92.9.4011.
Pubmed: 7732023
Mao J, Chirala SS, Wakil SJ: Human acetyl-CoA carboxylase 1 gene: presence of three promoters and heterogeneity at the 5'-untranslated mRNA region. Proc Natl Acad Sci U S A. 2003 Jun 24;100(13):7515-20. doi: 10.1073/pnas.1332670100. Epub 2003 Jun 16.
Pubmed: 12810950
Sinilnikova OM, Ginolhac SM, Magnard C, Leone M, Anczukow O, Hughes D, Moreau K, Thompson D, Coutanson C, Hall J, Romestaing P, Gerard JP, Bonadona V, Lasset C, Goldgar DE, Joulin V, Venezia ND, Lenoir GM: Acetyl-CoA carboxylase alpha gene and breast cancer susceptibility. Carcinogenesis. 2004 Dec;25(12):2417-24. doi: 10.1093/carcin/bgh273. Epub 2004 Aug 27.
Pubmed: 15333468
Jayakumar A, Tai MH, Huang WY, al-Feel W, Hsu M, Abu-Elheiga L, Chirala SS, Wakil SJ: Human fatty acid synthase: properties and molecular cloning. Proc Natl Acad Sci U S A. 1995 Sep 12;92(19):8695-9. doi: 10.1073/pnas.92.19.8695.
Pubmed: 7567999
Zody MC, Garber M, Adams DJ, Sharpe T, Harrow J, Lupski JR, Nicholson C, Searle SM, Wilming L, Young SK, Abouelleil A, Allen NR, Bi W, Bloom T, Borowsky ML, Bugalter BE, Butler J, Chang JL, Chen CK, Cook A, Corum B, Cuomo CA, de Jong PJ, DeCaprio D, Dewar K, FitzGerald M, Gilbert J, Gibson R, Gnerre S, Goldstein S, Grafham DV, Grocock R, Hafez N, Hagopian DS, Hart E, Norman CH, Humphray S, Jaffe DB, Jones M, Kamal M, Khodiyar VK, LaButti K, Laird G, Lehoczky J, Liu X, Lokyitsang T, Loveland J, Lui A, Macdonald P, Major JE, Matthews L, Mauceli E, McCarroll SA, Mihalev AH, Mudge J, Nguyen C, Nicol R, O'Leary SB, Osoegawa K, Schwartz DC, Shaw-Smith C, Stankiewicz P, Steward C, Swarbreck D, Venkataraman V, Whittaker CA, Yang X, Zimmer AR, Bradley A, Hubbard T, Birren BW, Rogers J, Lander ES, Nusbaum C: DNA sequence of human chromosome 17 and analysis of rearrangement in the human lineage. Nature. 2006 Apr 20;440(7087):1045-9. doi: 10.1038/nature04689.
Pubmed: 16625196
Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MS, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YS, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJ, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J: The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome Res. 2004 Oct;14(10B):2121-7. doi: 10.1101/gr.2596504.
Pubmed: 15489334
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