What happens to odd-numbered fatty acids during oxidation?

During the oxidation of odd-numbered fatty acids, the breakdown process leads to the formation of propionyl-CoA. Odd-numbered fatty acids typically yield acetyl-CoA units during beta-oxidation, but when the oxidation process reaches the final three-carbon unit, it results in the production of propionyl-CoA instead of just acetyl-CoA. Propionyl-CoA can then enter various metabolic pathways, including gluconeogenesis, where it can contribute to glucose production.

This process distinguishes odd-numbered fatty acids from even-numbered ones, which exclusively produce acetyl-CoA upon complete beta-oxidation. Moreover, the formation of propionyl-CoA emphasizes the unique aspect of odd-chain fatty acid metabolism, as it allows for a potential pathway to glucose synthesis, thereby linking fat metabolism with carbohydrate metabolism.