An LTB isomer which would not be formed either by known enzymatic or non-enzymatic processes. The enzymatic hydrolysis of LTA leads to LTB, which is the corresponding 5(S),12(R)-dihydroxy acid containing a 6(Z),8(E),10(E) conjugated triene. Non-enzymatic hydrolysis of LTA produces neither of the material, but instead produces both the 12(S) and 12(R) isomers of LTB in which the triene component now contains a 6-trans double bond. 12-epi (or 12(S)) LTB isomers which contain the natural 6-cis olefin are not produced either by enzymatic or by non-enzymatic processes. Further, 3-series LTs (derived from Mead acid) are only seen in essential fatty acid deficiency.
