The formation of products containing a conjugated tetraenoic system by pure reticulocyte lipoxygenase.

The pure lipoxygenase from reticulocytes converts 5,15-di-HETE at 2 degrees C to product(s) showing a characteristic UV spectrum with maxima of strong absorbance at 300 and 316 nm and shoulders at 285 and 350 nm. Their formation was completely prevented by the lipoxygenase inhibitors, ETYA and NDGA, by heating of the enzyme and by anaerobiosis. At 35 degrees C the products were formed only initially and in small amounts. The reaction products were purified by SP-HPLC and shown to migrate in the region of tri-HETEs in thin-layer chromatograms. The lipoxygenase from soybeans also converts 5,15-di-HETE to these product(s) with a comparable initial rate but different kinetics. These data suggest that 5,15-di-HETE is converted via a lipoxygenase reaction to 5,6,15-trihydroxy-7,9,11,13-(e,e,c,e)- and/or 5,14,15-trihydroxy-6,8,10,12-(e,c,e,e)-eicosatetraenoic acid, both of which contain a conjugated tetraene system.