Hydroperoxy-eicosatetraenoic

Figure 7. Dependence of BP oxidation by ram seminal vesicle micro-somes on the concentration of different hydroperoxides. Abbreviations used are 20 4, arachidonic acid 15-HPEA, 15-hydroperoxy-eicosatetraenoic acid t-BuOOH, t-butyl hydroperoxide. The structure is PGG2 is given in Figure 1.

Guido DM, McKenna R, Mathews WR. 1993. Quantitation of hydroperoxy- eicosatetraenoic acids and hydroxy-eicosatetraenoic acids as indicators of lipid peroxidation using gas chromatography-mass spectrometry. Anal Biochem 209 123-129. 

Lipoxygenase 5 converts arachidonic acid into 5-hydroperoxy-eicosatetraenoic acid (5-HPETE), which is the precursor of leukotrienes. Leukotrienes... 

This reaction was amrmg the earliest used for the GLC resolution of enantiomeric alcohols Studies 20 years ago showed that the reaction of (—)-menthyI chloroformate, [17], with chiral alcohols produced dia-stereomeric carbonates that could be resolved on packed columns (71,162). Despite its commercial availability, this CDA has been little used for the resolution of alcohols, Prelusky et al. (163) used [17] in a study of enantio-selecrive metabolic ketone reductions. The metabolite alcohols were deri-vatized with [17] and the derivatives were separated by capillary GLC. Good resolution was obtained under the chromatographic conditions used (163). The derivatization of warfarin with [17] and LC of the derivatives was described, but the peaks were not fully separated, even with retention times of 80-100 min (164). Brash et al. used CDA [17] to determine the enantiomeric composition of several enantiomeric pairs of hydroperoxy-eicosatetraenoic acids using silica LC, but some of the derivatives could not be resolved (165). It appears that [17] may be useful in the resolution of hydroxyl compounds and the evaluation of capillary GLC in the separations deserves attention. 

The acronym HPETE describes a hydroperoxy-eicosatetraenoic acid and a HETE is a monohydroxy-eicosanoid. Some examples are illustrated in Scheme 1.1. 

LTs are produced by the action of 5-lipoxygenase (5-LO) which inserts a diatomic oxygen at carbon atom-5 of AA yielding 5(5)-hydroperoxy eicosatetraenoic acid (5-HpETE). 

Lipoxygenases are a group of enzymes that oxidize polyunsaturated fatty acids possessing two cis double bonds separated by a methylene group to produce lipid hydroperoxides (19). Arachidonic acid is thus metabolized to a number of hydroperoxy-eicosatetraenoic acid... 

PREPARATION, PURIFICATION, CHARACTERIZATION AND ASSAY OF HYDROXY- AND HYDROPEROXY EICOSATETRAENOIC ACIDS... 

Preparation, purification, characterization and assay of hydroxy- and hydroperoxy-eicosatetraenoic acids J.M. BOEYNAEMS and l.C. HUBBARD... 

LT leukotriene, TX thromboxane, HPETE hydroperoxy eicosatetraenoic acid, hydroxy eicosatetraenoic acid, HHT12 hydroxyheptadecatrienoic acid (17 carbon), MDA malondialdehyde (3 carbon)... 

For over 40 years it has been known that plant tissues contain lipoxygenases which catalyse the introduction of oxygen into polyunsaturated fatty acids. In 1974 Hamberg and Samuelsson found that platelets contained a 12-lipoxygenase and since that time 5- and 15-lipoxygenases have also been discovered. The immediate products are hydroperoxy fatty acids which for arachidonate substrate are hydroperoxy eicosatetraenoic acids (HPETEs). 

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