D,L-2,6-Dimethylheptanoic acid

D,L-2,6-Dimethylheptanoic acid is a simple natural product derived in animal tissues from the metabolism of phytol by the oxidation of phytanic acid which results in the formation of 2,6-dimethylheptanoic acid along with other compounds.1 Phytanic acid and pristanic acid are initially oxidized in peroxisomes to 4,8-dimethylnonanoyl-CoA, which is converted to the corresponding acylcarnitine (presumably by peroxisomal carnitine octanoyltransferase), and exported to the mitochondrion. After transport across the mitochondrial membrane and transfer of the acylgroup to coenzyme A, further oxidation to 2,6-dimethylheptanoyl-CoA occurs.2 The alkyl chain of cholesterol contains 2,6-dimethylheptane which can be converted to 2,6-dimethylheptanoic acid during the degradation of cholesterol. (2R)-branched chain fatty acids cannot be enzymaticaly broken down but must first be converted to the (2S) configuration. A mitochondrial enzyme has been found to convert (2R,6)-dimethylheptanoyl-CoA to its (2S) stereoisomer.3