Methylmalonyl-CoA epimerase catalyzes the interconversion of the D and L isomers of methylmalonyl-CoA. This reaction is an important part of metabolism of propionyl-CoA, which arises from oxidation of odd-numbered fatty acids.

D-Methylmalonyl-CoA <=> L-Methylmalonyl-CoA (catalyzed by Methylmalonyl-CoA Epimerase)