PRODUCTION OF 3R-HYDROXY-POLYENOIC FATTY-ACIDS BY THE YEAST DIPODASCOPSIS-UNINUCLEATA

Various fatty acids were fed to the yeast Dipodascopsis uninucleata UO FS Y 128, and the extracted samples were analyzed for the accumulation of 3-hydroxy metabolites with the help of electron impact gas chromat ography-mass spectrometry. Fatty acids containing a 5Z,8Z-diene system (5Z,8Z,11Z-eicosatrienoic, 5Z,8Z,11Z,14Z-eicosatetraenoic, and 5Z,8Z, 11Z,14Z,17Z-eicosapentaenoic acids) yielded the corresponding 3-hydrox y-all-Z-eicosapolyenoic acids. Moreover, linoleic acid (9Z,12Z-octadec adienoic acid) and 11Z,14Z,17Z-eicosatrienoic acid were converted to t he 3-hydroxylated metabolites of shorter chain length, e.g., 3-hydroxy 5Z,8Z-tetradecadienoic acid and 3-hydroxy-5Z,8Z,11Z-tetradecatrienoic acid, respectively. In contrast, no accumulation of a 3-hydroxy metab olite was observed with oleic acid (9Z-octadecenoic acid), linolelaidi c acid (9E,12E-octadecadienoic acid), gamma-linolenic acid (6Z,9Z,12Z- octadecatrienoic acid), and eicosanoic acid as substrate. These findin gs pinpoint that the 3-hydroxylation of a fatty acid in Dipodascopsis uninucleata requires a 5Z,8Z-diene system either directly or following initial incomplete P-oxidation. Following analysis of the enantiomer composition, the arachidonic acid metabolite was identified as 3R-hydr oxy-5Z,8Z,11Z,14Z-eicosatetraenoic acid, which rules out a normal beta -oxidation as biosynthetic route to this new class of oxylipins.