Makrecka-Kuka 2017 Abstract MITOEAGLE Barcelona
Fatty acid oxidation evaluation in mitochondria.
Event: MitoEAGLE Barcelona 2017
Fatty acid oxidation (FAO) plays an important role in mitochondrial bioenergetics in skeletal muscle and heart tissues. Since FAO is a multi-step process in which various co-factors are involved, different forms of fatty acids are used to evaluate mitochondrial FAO. The most frequently used activated forms of fatty acids are palmitoyl-CoA, palmitoylcarnitine and octanoylcarnitine. The application of different activated fatty acids provides the possibility to characterize various steps in FAO processes. However, the interpretation of the obtained results is often misleading. Before being oxidized, fatty acids are activated to acyl-CoAs via long-chain acylCoA synthase. Before entering the β-oxidation pathway, acyl-CoAs have to be transported into the mitochondria. In contrast to medium- and short- chain acyl-CoAs, long-chain acyl-CoAs cannot directly pass the inner mitochondrial membrane, and their mitochondrial uptake is mediated by the L-carnitine-dependent transport system, which is rate-limiting step in FAO. As the first step, acyl-CoAs are converted to respective acylcarnitines by carnitine palmitoyltransferase I (CPT I). Formed acylcarnitines are subsequently transported into the mitochondria, where they are converted back to the respective acyl-CoAs by carnitine palmitoyltransferase II (CPT II) in the mitochondrial matrix. Moreover, the measurements of fatty acid oxidation in mitochondria are highly dependent on addition of co-factors like malate, carnitine and BSA.
Taking into account FAO biochemical pathway, the measurements using palmitoyl-CoA, palmitoylcarnitine and octanoylcarnitine characterize CPT I-dependent, CPT II-dependent and β-oxidation pathways, respectively.
Tissue;cell: Heart, Skeletal muscle
Regulation: Fatty acid
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