Hydroperoxide lyase in rabbit leukocytes: conversion of 15-hydroperoxyeicosatetraenoic acid to 15-keto-pentadeca-5,8,11,13-tetraenoic acid.

Incubation of 15-HPETE with rabbit peripheral blood leukocytes resulted in the generation of 8,15-diHETE, 14,15-diHETE, 5,15-diHETE, 15-HETE and a polar metabolite with a retention time on RP-HPLC of 9.5 min, U.V. max at 280 nm. Reduction of this polar metabolite with NaBH4 shifted the U.V. max to 233 nm, suggesting the presence of a conjugated dienone system. Electron impact GC/MS analysis on the polar metabolite revealed a structure of a C-15 short chain aldehyde: 15-keto-pentadeca 5,8,11,13-tetraenoic acid. The formation of this new metabolite is proposed to be catalyzed by the enzyme hydroperoxide lyase. Thus, it is possible that the presence of hydroperoxide lyase activity in leukocytes not only provide a new mechanism for the transformation of hydroperoxides it also may provide a de novo protective effect by controlling the level of intracellular arachidonic acid derived hydroperoxides as well as further prevented their clastogenic action and cellular damage.