Fatty Acid Oxidation

• Fatty acid oxidation involves bringing long-chain fatty acids into cells, such as heart muscle, skeletal muscles, and the liver, where they are broken down for energy
• In the first step of fatty acid oxidation, a fatty acid is converted to a fatty acyl-CoA molecule by the enzyme fatty acyl-CoA synthetase, requiring the addition of a CoA group using ATP
• To transport the fatty acyl-CoA into the mitochondria for further breakdown, it combines with carnitine, forming fatty acyl carnitine, which is then transported through the mitochondrial membrane by carnitine acyl transferase type 1
• The first step in beta-oxidation involves removing a hydrogen from the fatty acid, forming a double bond between the alpha and beta carbons
• The enzyme catalyzing the removal of hydrogen in the first step is a fatty acyl CoA dehydrogenase
• The second step in beta-oxidation is the hydration of the double bond, where water is added across the bond by an enzyme called enoyl CoA hydratase
• The molecule involved in the second step is trans Delta 2 enoyl CoA
• In the third step of beta-oxidation, an enzyme helps NAD+ turn into NADH, forming a double bond between the oxygen and the beta carbon, resulting in beta-hydroxyacyl CoA
• The enzyme catalyzing the third step is involved in converting NAD+ into NADH is a dehydrogenase
• The fourth step in beta-oxidation involves the formation of a ketone on the beta carbon, resulting in beta-ketoacyl CoA
• Beta oxidation is a process that breaks down fatty acids into acetyl-CoA molecules
• In the first step of beta oxidation, an enzyme called acyl-CoA dehydrogenase catalyzes the conversion of the fatty acyl group to trans-delta2-enoyl-CoA
• The third step of beta oxidation is facilitated by an enzyme called L-3-hydroxyacyl-CoA dehydrogenase, which converts L-3-hydroxyacyl-CoA to 3-ketoacyl-CoA
• Thiolase adds a CoA molecule to the beta carbon after breaking the bond between the alpha and beta carbon
• Beta oxidation produces acetyl-CoA molecules, which can enter the Krebs cycle to generate NADH, FADH2, and ATP through oxidative phosphorylation
• The purpose of beta oxidation is to produce acetyl-CoA molecules from fatty acids when blood glucose levels are low, providing an alternative fuel source
• Odd-chain fatty acids and beta oxidation in peroxisomes are also topics related to fatty acid metabolism that will be covered in the next part of the course