(2S-(2 alpha,3 beta(1E,3E,5Z,8Z)))-3-(1,3,5,8-Tetradecatetraenyl)oxiranebutanoic acid. An unstable allylic epoxide, formed from the immediate precursor 5-HPETE via the stereospecific removal of a proton at C-10 and dehydration. Its biological actions are determined primarily by its metabolites, i.e., leukotriene b4 and cysteinyl-leukotrienes. Alternatively, leukotriene a4 is converted into leukotriene c4 by glutathione-S-transferase or into 5,6-di-HETE by the epoxide-hydrolase. (From dictionary of prostaglandins and Related Compounds, 1990)