Structural requirements of acetylenic fatty acids for inhibition of soybean lipoxygenase and prostaglandin synthetase

Abstract

The conversion of linoleic acid to its hydroperoxide by soybean lipoxygenase and the conversion of arachidonic acid to prostaglandin E 2 by a preparation of sheep seminal vesicles, both previously shown to be irreversibly inhibited by eicosa-5,8,11, 14-tetraynoic acid, are similarly inhibited by octadeca-9,12-diynoic acid. No other member of a series of ten diynoic fatty acids, nor any of fifteen positional isomers of octadecynoic acid, showed detectable inhibition. Of a group of four isomeric octadecenynoic acids, having one acetylenic and either a cis- or trans-ethylenic bond in the 9 or 12 positions, none significantly inhibited soybean lipoxygenase, whereas only one, octadec-cis-9-en-12-ynoic acid failed to strongly inhibit prostaglandin synthesis.