Myeloperoxidase, a catalyst for lipoprotein oxidation, is expressed in human atherosclerotic lesions.

Chlorotyrosine promotes human aortic smooth muscle cell migration through increasing superoxide anion production and ERK1/2 activation

“…It catalyzes the two-electron peroxidation of chloride to generate hypochlorous acid (HOCl) [2], a potent chlorinating oxidant, capable of chlorinating tyrosine into chlorotyrosine. Levels of chlorotyrosine are increased in atherosclerotic tissues [3] and the blood of in patients with inflammatory conditions including atherosclerosis [4,25,26]. The chlorination of apolipoprotein A-I was found to impair its cardioprotective ability to remove excess cellular cholesterol from lipid-laden macrophages in the artery wall [5].…”

When and why a water-soluble antioxidant becomes pro-oxidant during copper-induced low-density lipoprotein oxidation: a study using uric acid

“…Little is known about the molecular mechanisms underlying LDL oxidation in i o, but reactions involving transition metals, such as copper and iron [6], free radicals [6], hypochlorous acid [7], peroxynitrite [8] and the activity of selected enzymes, such as myeloperoxidase [9] and lipoxygenase [10], have been alternatively claimed to play a role. Experimental, clinical and epidemiological data indicate, in addition, that these processes can be efficiently halted by either LDL-associated (lipid-soluble) and non-associated (water-soluble) antioxidants [11].…”

Dual Functionality of Myeloperoxidase in Rotenone-Exposed Brain-Resident Immune Cells

“…MPO has been closely involved in stimulating mitogen-activated protein kinase activity, cell growth, and protease activity, thereby influencing the immune responses and the progression of several inflammation-associated diseases. 10,[15][16][17][18][19] Until recently, phagocytic blood cells were thought to be the only cellular sources of MPO. However, recent studies 18,20,21 have shown that several cell types, including neuronal cells, express MPO under certain pathological conditions.…”