Uremic albumin blocks reverse cholesterol transfer: role of lysine modifications

Background Due to a lack of antioxidant enzymes in plasma, plasma proteins are preferential targets of oxidant injury. Reaction of chlorinated oxidants (e.g. hypochlorous acid), generated from activated neutrophils, with plasma albumin gives rise to formation of an oxidized protein fraction, termed advanced oxidation protein products (AOPPs). AOPPalbumin is a potent high-density lipoprotein (HDL) receptor antagonist, blocking HDL association and reverse cholesterol transport (RCT). However, it is not known whether structural alterations and/or an increase in negative charge (through oxidation of positively charged lysine residues on albumin) are required for high affinity binding to SR-BI.