Racemization of 2-methyl-branched fatty acid CoA esters. Responsible for the conversion of pristanoyl-CoA and C27-bile acyl-CoAs to their (S)-stereoisomers. Has a role in drug metabolism as well as probably in lipid metabolism. The 2-arylpropionic acid (2-APA's) derivatives, including ibuprofen, are the most widely used anti-inflammatory analgesic cyclooxygenase inhibitors. The (-)-R-enantiomer, which is inactive in terms of cyclooxygenase inhibition, is epimerized in vivo via this enzyme to the cyclooxygenase-inhibiting (+)-S-enantiomer.