Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/6/1997
Publication Date: N/A
Technical Abstract: Previous work by us has shown that the lipoxygenase pathway product, 3Z-nonenal, is the precursor of 4-hydroxy-2E-nonenal (4-HNE) in soybean, Glycine max. Because 4-HNE appears to be a lipid signal in animal systems by activating phospholipase-C and -D, there is interest in the origin of 4-HNE. However, the biosynthesis of 4-HNE in animals has not yet been determined. In previous work, it was reported that the initial product of 3Z-nonenal oxidation is 4-hydroperoxy-2E-nonenal (4-HPNE), and a hydroperoxide-dependent peroxygenase is thought to reduce the 4-hydroperoxide to 4-hydroxide. In this work, we have attempted to purify the hydroperoxide-producing oxygenase. Chromatography on various supports has shown that oxygen uptake with 3Z-nonenal substrate coincides with lipoxygenase-1 activity. Compared to oxidation of lipoxygenase's preferred substrate, linoleic acid, the activity with 3Z-nonenal was about 400- to 1000-fold less active. Rather than obtaining the expected product, 4-HPNE, preliminary gas chromatography/mass spectrometry evidence has shown that the principal product of lipoxygenase action on 3Z-nonenal is 4-oxo-2-nonenal, presumably arising from the alkoxyl radical of 4-HPNE. It is not yet certain if lipoxygenase is a significant contributor to 4-HNE biosynthesis.