FATTY-ACID BIOSYNTHESIS IN THE DEVELOPING ENDOSPERM OF COCUS-NUCIFERA

Endosperm tissue of developing coconut endosperm incorporated [14C] acetate and [14C]-malonate into [14C]C8-C18 fatty acids. The distribution of [14C] label into the various fatty acids mimicked the distribution of endogenous fatty acids at early and middle stages of endosperm development. Although [14C] C8-C18 fatty acids were taken up rapidly by endosperm tissue slices, no elongation occurred; [14C] stearic acid was not desaturated to oleic. Cell free preparations have also been obtained from this tissue that readily incorporated [14C] malonyl-CoA into a range of [14C] fatty acids in the presence of ACP and NADH at pH 7.0. Employing this system, a number of experiments were designed to determine the mechanism of chain length termination. In contrast to intact tissue slice experiments, cell-free extracts yielded as principal products palmitic and stearic acid, although up to 20% were shorter chain acids. A number of possible mechanisms for chain length termination were proposed and tested. © 1979 American Oil Chemists' Society.