Conversion of oleic acid to linoleic acid.

Reports from this laboratory have described the formation of palmitoleic and oleic acids from their saturated counterparts by enzyme systems of yeast (2, 3). For introducing a double bond into the 9,lO position of the aliphatic chain, the desaturating enzymes, acting on the coenzyme A derivatives of the fatty acids, require reduced triphosphopyridine nucleotide, and molecular oxygen as hydrogen acceptor. Extending these studies to a multiply unsaturated system, we have now investigated the biosynthesis of linoleic acid. This paper deals with the role of oleic acid as a precursor for linoleic acid and with the nature of the processes which introduce the second double bond of the diolefine system. Torulopsis utilis, a lipid-rich yeast known to contain large amounts of linoleate (4), has been found to form this acid efficiently from oleate.