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 transformation. 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 mt-outer 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 mt-inner membrane, and supplies electrons from fatty acid β-oxidation (FAO) to CoQ.
Abbreviation: FAO
Reference: Gnaiger 2019 MitoPathways
MitoPedia O2k and high-resolution respirometry:
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Talk:Fatty acid oxidation
FAO and HRR
- 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.
SUITbrowser question: Fatty acid oxidation
- SUIT protocols can assess the respiration stimulated by fatty acid oxidation, with the participation of the electron-transferring flavoprotein complex.
- The SUITbrowser can be used to find the best SUIT protocols to answer this and other research questions.
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 biopsies of human muscle. Methods Mol Biol 810:25-58. »Bioblast Access«
- ↑ Oliveira AF, Cunha DA, Ladriere L, Igoillo-Esteve M, Bugliani M, Marchetti P, Cnop M (2015) In vitro use of free fatty acids bound to albumin: A comparison of protocols. Biotechniques 58:228-33. »Open Access«
- » O2k-Network discussion forum: fatty acids used in permeabilized fibre assays
- » F-pathway control state
MitoPedia methods:
Respirometry
MitoPedia topics:
Substrate and metabolite