4-hydroxynonenal adduct 156.1150360107421875 156.220001220703125 4-hydroxynonenal (HNE) 4-hydroxynonenal, a toxic lipid aldehyde, is a product of the hydroperoxide beta-cleavage degradation of omega-6 polyunsaturated fatty acids, such as arachidonic and linoleic acids [JSG]. A protein modification produced by formation of an adduct of a residue with 4-hydroxynonenal. C 9 H 16 O 2 HNE MOD:00446 PSI-MOD Unimod:53 X artifact lipoconjugated residue