Myeloperoxidase binds to low-density lipoprotein: potential implications for atherosclerosis.
Myeloperoxidase (MPO), an abundant heme enzyme released by activated phagocytes, catalyzes the formation of a number of reactive species that can modify low-density lipoprotein (LDL) to a form that converts macrophages into lipid-laden or 'foam' cells, the hallmark of atherosclerotic lesions. Since MPO has been shown to bind to a number of different cell types, we investigated binding of MPO to LDL. Using the precipitation reagents phosphotungstate or isopropanol, MPO co-precipitated with LDL, retaining its catalytic activity. The association of MPO with LDL was confirmed using native gel electrophoresis. MPO was also found to co-precipitate with apolipoprotein B-100-containing lipoproteins in whole plasma. No precipitation of MPO was observed in lipoprotein-deficient plasma, and there was a dose-dependent increase in precipitation following addition of LDL to lipoprotein-deficient plasma. Binding of MPO to LDL could potentially enhance site-directed oxidation of the lipoprotein and limit scavenging of reactive oxygen species by antioxidants.
Carr
A C
AC
Linus Pauling Institute, Oregon State University, 571 Weniger Hall, Corvallis, OR 97331-6512, USA. anitra.carr@orst.edu
Myzak
M C
MC
Stocker
R
R
McCall
M R
MR
Frei
B
B
D001161:Arteriosclerosis / Q000097:blood*; D006801:Humans; D007700:Kinetics; D007962:Leukocytes / Q000201:enzymology; D008077:Lipoproteins, LDL / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D009195:Peroxidase / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D011485:Protein Binding; D012709:Serum Albumin
D008077:Lipoproteins, LDL; D012709:Serum Albumin; D009195:Peroxidase