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Pathway Description
Fatty Acid Biosynthesis
Rattus norvegicus
Category:
Metabolite Pathway
Sub-Category:
Metabolic
Created: 2018-08-10
Last Updated: 2019-08-16
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
Lopez-Casillas F, Bai DH, Luo XC, Kong IS, Hermodson MA, Kim KH: Structure of the coding sequence and primary amino acid sequence of acetyl-coenzyme A carboxylase. Proc Natl Acad Sci U S A. 1988 Aug;85(16):5784-8. doi: 10.1073/pnas.85.16.5784.
Pubmed: 2901088
Luo XC, Park K, Lopez-Casillas F, Kim KH: Structural features of the acetyl-CoA carboxylase gene: mechanisms for the generation of mRNAs with 5' end heterogeneity. Proc Natl Acad Sci U S A. 1989 Jun;86(11):4042-6. doi: 10.1073/pnas.86.11.4042.
Pubmed: 2566999
Saad Y, Garrett MR, Manickavasagam E, Yerga-Woolwine S, Farms P, Radecki T, Joe B: Fine-mapping and comprehensive transcript analysis reveals nonsynonymous variants within a novel 1.17 Mb blood pressure QTL region on rat chromosome 10. Genomics. 2007 Mar;89(3):343-53. doi: 10.1016/j.ygeno.2006.12.005. Epub 2007 Jan 10.
Pubmed: 17218081
Amy CM, Witkowski A, Naggert J, Williams B, Randhawa Z, Smith S: Molecular cloning and sequencing of cDNAs encoding the entire rat fatty acid synthase. Proc Natl Acad Sci U S A. 1989 May;86(9):3114-8. doi: 10.1073/pnas.86.9.3114.
Pubmed: 2717611
Beck KF, Schreglmann R, Stathopulos I, Klein H, Hoch J, Schweizer M: The fatty acid synthase (FAS) gene and its promoter in Rattus norvegicus. DNA Seq. 1992;2(6):359-86.
Pubmed: 1339331
Amy CM, Williams-Ahlf B, Naggert J, Smith S: Intron-exon organization of the gene for the multifunctional animal fatty acid synthase. Proc Natl Acad Sci U S A. 1992 Feb 1;89(3):1105-8. doi: 10.1073/pnas.89.3.1105.
Pubmed: 1736293
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 SMP0000456
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