Oxidized low-density lipoprotein (oxLDL) particles contain low molecular weight species that are cytotoxic and pro-atherogenic. Many of these substances were isolated and purified from oxLDL, identified as phosphatidylcholine species containing a fragmented, oxidized short-chain fatty acid remnant at the sn-2 position. PAz-PC is one of the predominant oxLDL species and may be an important structural determinant of oxLDL.