Pathway for the Synthesis of Fatty Acids in Mammalian Tissues

Abstract

Fatty acid synthetase of the liver of all of the mammalian species investigated and of the lactating mammary gland shows a pronounced preference for butyryl-CoA over acetyl-CoA as primer in the synthesis of fatty acids from the primer, malonyl-CoA and NADPH. This relative primer specificity, in contrast to that of the enzyme complex isolated from rat adipose or pigeon liver, appears to be related to the presence in the particle-free supernatant of enzymes which are capable of synthesizing butyryl-CoA from acetyl-CoA by the reversal of β oxidation. A high proportion of fatty acid synthesis from acetyl-CoA by the mammalian liver and mammary supernatant, which contained NADH, NADPH and malonyl-CoA, occurred after its initial conversion to butyryl-CoA.