Note: a dashed line (without arrowheads) between two compound names is meant to imply that the two names are just different instantiations of the same compound -- i.e. one may be a specific name and the other a general name, or they may both represent the same compound in different stages of a polymerization-type pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Locations of Mapped Genes:
|Superclasses:||Degradation/Utilization/Assimilation → Fatty Acid and Lipids Degradation → Fatty Acids Degradation|
Although enzymes of the pathway handle both short and long chain fatty acids, it is the long chain compounds that induce the enzymes of the pathway [Clark81]. Each turn of the cycle removes two carbon atoms until only two or three remain. When even-numbered fatty acids are broken down, a two-carbon compound remains, acetyl-CoA. When odd number fatty acids are broken down, a three-carbon residue results, propionylCoA. This is further catabolized by the reactions of proprionate catabolism. Unsaturated fatty acids, with cis double bonds located at odd-numbered carbon atoms, enter the main pathway of saturated fatty acid degradation by converting related metabolites of cis configuration and D stereoisomers, derived from breakdown of unsaturated fatty acids, to the trans- or L isomers of saturated fatty acid breakdown by an isomerase and an epimerase, respectively. When cis double bonds are located at even-numbered carbon atoms, such as linoleic acid (cis,cis(9,12)-octadecadienoic acid), after the fatty acid is degraded to the ten carbon stage an extra step is required to deal with the resulting compound, trans,δ(2)-cis,δ(4)decadienoyl-CoA. The enzyme 2,4-dienoyl-CoA reductase, E.C. 126.96.36.199, converts this to trans,δ(2)decenoyl-CoA which enters the normal cycle at the point of the isomerase.
More recently, an anaerobic pathway of fatty acid metabolism has been characterized [Campbell03]. Anaerobic β-oxidation of fatty acids utilizes fumarate as the terminal electron acceptor [MorganKiss04]. In contrast to the aerobic pathway, octanoate and decanoate can serve as substrates for the anaerobic fatty acid oxidation pathway [Campbell03]. In the anaerobic pathway FadI, FadJ, and FadK serve functions parallel to those of FadA, FadB, and FadD in the aerobic pathway [Campbell03].
The glyoxylate cycle is necessary for anaerobic or aerobic fatty acid oxidation to provide the carbon and energy for cell growth [Campbell03].
Campbell03: Campbell JW, Morgan-Kiss RM, E Cronan J (2003). "A new Escherichia coli metabolic competency: growth on fatty acids by a novel anaerobic beta-oxidation pathway." Mol Microbiol 47(3);793-805. PMID: 12535077
Beloin04: Beloin C, Valle J, Latour-Lambert P, Faure P, Kzreminski M, Balestrino D, Haagensen JA, Molin S, Prensier G, Arbeille B, Ghigo JM (2004). "Global impact of mature biofilm lifestyle on Escherichia coli K-12 gene expression." Mol Microbiol 51(3);659-74. PMID: 14731270
Black92: Black PN, DiRusso CC, Metzger AK, Heimert TL (1992). "Cloning, sequencing, and expression of the fadD gene of Escherichia coli encoding acyl coenzyme A synthetase." J Biol Chem 1992;267(35);25513-20. PMID: 1460045
Black97: Black PN, Zhang Q, Weimar JD, DiRusso CC (1997). "Mutational analysis of a fatty acyl-coenzyme A synthetase signature motif identifies seven amino acid residues that modulate fatty acid substrate specificity." J Biol Chem 272(8);4896-903. PMID: 9030548
Chen94a: Chen D, Swenson RP (1994). "Cloning, sequence analysis, and expression of the genes encoding the two subunits of the methylotrophic bacterium W3A1 electron transfer flavoprotein." J Biol Chem 269(51);32120-30. PMID: 7798207
Dellomonaco11: Dellomonaco C, Clomburg JM, Miller EN, Gonzalez R (2011). "Engineered reversal of the β-oxidation cycle for the synthesis of fuels and chemicals." Nature 476(7360);355-9. PMID: 21832992
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
He96: He XY, Yang SY (1996). "Histidine-450 is the catalytic residue of L-3-hydroxyacyl coenzyme A dehydrogenase associated with the large alpha-subunit of the multienzyme complex of fatty acid oxidation from Escherichia coli." Biochemistry 1996;35(29);9625-30. PMID: 8755745
Hsu91: Hsu L, Jackowski S, Rock CO (1991). "Isolation and characterization of Escherichia coli K-12 mutants lacking both 2-acyl-glycerophosphoethanolamine acyltransferase and acyl-acyl carrier protein synthetase activity." J Biol Chem 1991;266(21);13783-8. PMID: 1649829
Ishizaki06: Ishizaki K, Schauer N, Larson TR, Graham IA, Fernie AR, Leaver CJ (2006). "The mitochondrial electron transfer flavoprotein complex is essential for survival of Arabidopsis in extended darkness." Plant J 47(5);751-60. PMID: 16923016
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