A relationship which distinguishes those fatty acids that support the growth of oxygen-deprived Saccharomyces cerevisiae from those that do not was found. To function properly, a long chain of saturated carbon atoms appears to require interruption by an appropriate chemical group such that only a maximum number of contiguous saturated carbon atoms is present anywhere in the chain. A double bond was found to serve as an interrupting group, and for 19 cis-unsaturates studied, ranging from C14:1-Δ9 to C22:6-Δ4,7,10,13,16,19, the number of saturated C atoms was 9. The chain length and the position and number of double bonds had no influence in determining whether the acids were active or inactive except as these structural features related to the interruption rule. Although less extensively examined, a hydroxyl group or trans-double bond also appeared to act as an interrupting group with allowed numbers of 9 and 7, respectively, for saturated C atoms. Oxygen deprivation did not result in a shift to shorter chain length of the saturates formed, and the presence of unsaturates did not prevent biosynthesis of saturates.
- oleic acid
- polyunsaturated fatty acids