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Table 5 Origin, enzymatic pathways of reactive oxygen species, and their oxidized products.

From: Homocysteine and reactive oxygen species in metabolic syndrome, type 2 diabetes mellitus, and atheroscleropathy: The pleiotropic effects of folate supplementation

Origin – Location Enzymatic Pathway ROS Potent Oxidants PRODUCTS Oxidized lipids and Proteins
Mitochondrial Respiratory Chain O2 -OH Oxidized lipids, proteins, nucleic acids, and autoxidation byproducts.
Inflammatory Macrophage Membraneous NAD(P)H Oxidase O2 OH H2O2 Advanced Lipoxidation Endproducts (ALE) Ortho o-tyrosine Meta m- tyrosine
Granular Myeloperoxidase (MPO) Hypochlorous Acid HOCL (bleach) Tyr NO2 3-Chlorotyrosine di-Tyrosine NO2-Tyrosine (Nitrotyrosine)
Macrophage Nitric Oxide Synthase (NOS) Inducible (iNOS) Large bursts uncontrolled ONOO' NO2-Tyr (Nitrotyrosine)
Endothelial Cell   
Nitric Oxide Synthase (NOS) Constitutive (cNOS) eNOS → NO nNOS → NO Small bursts (puffs) controlled NO + O2 → ONOO' ONOO' NO2-Tyr (Nitrotyrosine) NO2-Tyr
eNOS derived NO NO: the GOOD Natural Occurring, Local Occurring, Chain Breaking Antioxidant
Superoxide O 2 .: the BAD  
Peroxynitrite ONOO : the UGLY  
Hypochlorous acid HCLO : the UGLY  
Restoration of endothelial derived NITRIC OXIDE Via the eNOS reaction.. ANTIOXIDANT ANTIREDOXIDANT → → → Prevention of the devastating effects of ROS.
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