BIO-OXIDATION OF LINOLEIC ACID VIA METHYLMALONYL-COA

Unsaturated long-chain fatty acids are oxidized more rapidly than are saturated fatty acids of similar chain length in intact animals and isolated mitochondria. Gamma-oxidation of the 3-dodecenoic acid intermediate in beta-oxidation of oleate would yield propionate which is metabolized via methylmalonate. 14C-labeled fatty acids were administered to intact rats, muscle homogenates and lysed mitochondria. Methylmalonate, succinate and CO 2 were isolated and 14C determined. Incorporation of U- 14C-linoleate into methylmalonate in vitro was 20 times greater than from U- 14C-palmitate. Rats fed 20% corn oil grew more slowly on B 12 deficient than B 12 sufficient diets. Biotin and vitamin B 12 deficiencies were found to decrease the in vivo metabolism of linoleate. These data suggest that one pathway of linoleate oxidation has methylmalonate as an intermediate. © 1969 The American Oil Chemists' Society.