Difference between revisions of "Fatty acid oxidation"
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|description='''Fatty acid oxidation''' (β-oxidation) is a multi-step process by which fatty acids are broken down to generate acetyl-CoA, NADH and FADH<sub>2</sub> for further energy production. Fatty acids (short chain with 4–8, medium-chain with 6–12, long chain with 14-22 carbon atoms) are activated by fatty acyl-CoA synthases (thiokinases) in the cytosol. The outer mt-membrane enzyme [[carnitine palmitoyltransferase I]] (CPT 1) generates an acyl-carnitine intermediate for transport into the mt-matrix. [[Octanoate]], but not [[palmitate]], (eight- and 16-carbon saturated fatty acids) may pass the mt-membranes, but both are frequently supplied to mt-preparations in the activated form of [[octanoylcarnitine]] or [[palmitoylcarnitine]]. | |description='''Fatty acid oxidation''' (β-oxidation) is a multi-step process by which fatty acids are broken down to generate acetyl-CoA, NADH and FADH<sub>2</sub> for further energy production. Fatty acids (short chain with 4–8, medium-chain with 6–12, long chain with 14-22 carbon atoms) are activated by fatty acyl-CoA synthases (thiokinases) in the cytosol. The outer mt-membrane enzyme [[carnitine palmitoyltransferase I]] (CPT 1) generates an acyl-carnitine intermediate for transport into the mt-matrix. [[Octanoate]], but not [[palmitate]], (eight- and 16-carbon saturated fatty acids) may pass the mt-membranes, but both are frequently supplied to mt-preparations in the activated form of [[octanoylcarnitine]] or [[palmitoylcarnitine]]. | ||
[[Electron-transferring flavoprotein complex]] (CETF) is located on the matrix face of the inner mt-membrane, and supplies electrons from fatty acid β-oxidation (FAO) to CoQ. FAO cannot proceed without a substrate combination of fatty acids & [[malate]], and inhibition of CI blocks FAO completely. Fatty acids are split stepwise into two carbon fragments forming acetyl-CoA, which enters the TCA cycle by condensation with oxaloacetate (CS reaction). Therefore, FAO implies simultaneous electron transfer into the [[Q-junction]] | [[Electron-transferring flavoprotein complex]] (CETF) is located on the matrix face of the inner mt-membrane, and supplies electrons from fatty acid β-oxidation (FAO) to CoQ. FAO cannot proceed without a substrate combination of fatty acids & [[malate]], and inhibition of CI blocks FAO completely. Fatty acids are split stepwise into two carbon fragments forming acetyl-CoA, which enters the TCA cycle by condensation with oxaloacetate (CS reaction). Therefore, FAO implies simultaneous electron transfer into the [[Q-junction]] through CETF and CI. | ||
|info=Gnaiger 2014 MitoPathways | |info=[[Gnaiger 2014 MitoPathways]] | ||
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{{MitoPedia methods | {{MitoPedia methods | ||
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|mitopedia topic=Substrate and metabolite | |mitopedia topic=Substrate and metabolite | ||
}} | }} | ||
== FAO and HRR == | |||
{{Technical support integrated}} [[Talk:Fatty acid oxidation]] | |||
Studies with FAO in mt-preparations are conducted with mitochondrial respiration media (MiR05Cr, [[MiR06]], etc.) with fatty acid-free [[BSA]] <ref> Lemieux H, Semsroth S, Antretter H, Höfer D, Gnaiger E (2011) Mitochondrial respiratory control and early defects of oxidative phosphorylation in the failing human heart. Int J Biochem Cell Biol 43:1729–38. [[Lemieux 2011 Int J Biochem Cell Biol |»Bioblast Access«]] </ref>, | |||
<ref> Pesta D, Hoppel F, Macek C, Messner H, Faulhaber M, Kobel C, Parson W, Burtscher M, Schocke M, Gnaiger E (2011) Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans. Am J Physiol Regul Integr Comp Physiol 301:R1078–87. [[Pesta 2011 Am J Physiol Regul Integr Comp Physiol |»Open Access«]] </ref>, | |||
<ref> Pesta D, Gnaiger E (2012) High-resolution respirometry. OXPHOS protocols for human cells and permeabilized fibres from small biopisies of human muscle. Methods Mol Biol 810:25-58. [[Pesta 2012 Methods Mol Biol |»Bioblast Access«]] </ref>. | |||
The use of fatty-acid free BSA is very important when providing fatty acids in vitro, to buffer the free FA concentration and thus avoid FA toxicity <ref> http://www.biotechniques.com/multimedia/archive/00249/BTN_A_000114285_O_249756a.pdf </ref>. | |||
: [[Gnaiger E]], 2015-05-15 | |||
== References == | |||
<references/> |
Revision as of 16:09, 16 May 2015
Description
Fatty acid oxidation (β-oxidation) is a multi-step process by which fatty acids are broken down to generate acetyl-CoA, NADH and FADH2 for further energy production. Fatty acids (short chain with 4–8, medium-chain with 6–12, long chain with 14-22 carbon atoms) are activated by fatty acyl-CoA synthases (thiokinases) in the cytosol. The outer mt-membrane enzyme carnitine palmitoyltransferase I (CPT 1) generates an acyl-carnitine intermediate for transport into the mt-matrix. Octanoate, but not palmitate, (eight- and 16-carbon saturated fatty acids) may pass the mt-membranes, but both are frequently supplied to mt-preparations in the activated form of octanoylcarnitine or palmitoylcarnitine.
Electron-transferring flavoprotein complex (CETF) is located on the matrix face of the inner mt-membrane, and supplies electrons from fatty acid β-oxidation (FAO) to CoQ. FAO cannot proceed without a substrate combination of fatty acids & malate, and inhibition of CI blocks FAO completely. Fatty acids are split stepwise into two carbon fragments forming acetyl-CoA, which enters the TCA cycle by condensation with oxaloacetate (CS reaction). Therefore, FAO implies simultaneous electron transfer into the Q-junction through CETF and CI.
Abbreviation: FAO
Reference: Gnaiger 2014 MitoPathways
MitoPedia methods:
Respirometry
MitoPedia topics:
Substrate and metabolite
FAO and HRR
MitoPedia O2k and high-resolution respirometry:
O2k-Open Support
Studies with FAO in mt-preparations are conducted with mitochondrial respiration media (MiR05Cr, MiR06, etc.) with fatty acid-free BSA [1], [2], [3].
The use of fatty-acid free BSA is very important when providing fatty acids in vitro, to buffer the free FA concentration and thus avoid FA toxicity [4].
- Gnaiger E, 2015-05-15
References
- ↑ Lemieux H, Semsroth S, Antretter H, Höfer D, Gnaiger E (2011) Mitochondrial respiratory control and early defects of oxidative phosphorylation in the failing human heart. Int J Biochem Cell Biol 43:1729–38. »Bioblast Access«
- ↑ Pesta D, Hoppel F, Macek C, Messner H, Faulhaber M, Kobel C, Parson W, Burtscher M, Schocke M, Gnaiger E (2011) Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans. Am J Physiol Regul Integr Comp Physiol 301:R1078–87. »Open Access«
- ↑ Pesta D, Gnaiger E (2012) High-resolution respirometry. OXPHOS protocols for human cells and permeabilized fibres from small biopisies of human muscle. Methods Mol Biol 810:25-58. »Bioblast Access«
- ↑ http://www.biotechniques.com/multimedia/archive/00249/BTN_A_000114285_O_249756a.pdf