Fig. 1
Schematic overview of the human hepatic mitochondrial fatty acid oxidation model. Enzyme names are written in white with their chain length specificity as subscript (C16, for example, for a 16-carbon acyl group). The enzymes depicted in green are membrane-bound enzymes while the blue boxes indicate soluble enzymes. These enzymes interconvert metabolites (in black text). Subscripts identify the metabolites’ chain lengths (Long or Short & Medium) and their primary localization according to their solubility. Metabolites in red are present at constant concentrations: ETFox and ETFred refer to the oxidised and reduced form of the electron-transferring flavoprotein, and FFA indicates free fatty acids. Free coenzyme A (CoASH; yellow boxes) and L-carnitine (L-car; black boxes) are the non-acylated fraction of CoA and L-carnitine, of which the total pool forms a conserved moiety. The model includes the following enzymes: carnitine palmitoyltransferase 1a (CPT1; EC 2.3.1.21), carnitine/acylcarnitine translocase (CACT; PathwayCommons: O43772), carnitine palmitoyltransferase 2 (CPT2; EC 2.3.1.21), carnitine acetyltransferase (CrAT; EC 2.3.1.137), very-long-chain acyl-CoA dehydrogenase (VLCAD; EC 1.3.8.9), medium-chain acyl-CoA dehydrogenase (MCAD; EC 1.3.8.7), short-chain acyl-CoA dehydrogenase (SCAD; EC 1.3.8.1), crotonase (CROT; EC 4.2.1.17), medium- and short-chain hydroxyacyl-CoA dehydrogenase (M/SCHAD; EC 1.1.1.35), medium-chain ketoacyl-CoA thiolase (MCKAT; EC 2.3.1.16), mitochondrial trifunctional protein (MTP: EC 4.2.1.17, EC 1.1.1.211, EC 2.3.1.16), coenzyme A-insensitive acyl-CoA thioesterase (ACOTci; equivalent to ACOT2; EC 3.1.2.2), coenzyme A-sensitive acyl-CoA thioesterase (ACOTcs; equivalent to ACOT7 and ACOT13 combined; EC 3.1.2.2)