IX. Mitochondrial beta-oxidation
Additional Enzymes: Propionyl CoA
Handling the three-carbon propionyl CoA
Fatty acids with an odd number of carbons in their chains require a
means of handling the three-carbon propionyl CoA that is the final
fragment produced by beta-oxidation of such a chain:
- The first step is carboxylation by the biotin-dependent
propionyl CoA carboxylase in an ATP-requiring reaction.
- The D- isomer, which is the product, is then converted to the L- isomer by
methylmalonyl CoA racemase.
- In the final step, the L- isomer is converted to succinyl CoA by
methylmalonyl CoA mutase.
- Succinyl CoA can then be metabolized through the tricarboxylic acid cycle.