Table 6 |
|
Antioxidants: catalytic – enzymatic inactivation of free radicals. |
| Enzymatic Antioxidants |
| SUPER OXIDE DISMUTASE (SOD)[O2- + SOD → H2O2 + O2] ecSOD (extracellular) MnSOD (mitochondrial) CuZnSOD (intracellular) |
| CATALASE– Location: peroxisome [2H2O2 + catalase → 2 H2O + O2] |
| GLUTATHIONE PEROXIDASE– Location: mitochondrion – cytosol and systemic circulation. (Glutamyl-cysteinyl-glycine
tripeptide) glutathione reduced -SH to the oxidized disulfide GSSG. (Glutathione peroxidase)
[GSH + 2H2O2 → GSSG + H2O + O2] (Glutathione reductase) [GSSG → GSH] at the expense of [NADH → NAD+] and/or [NAD(P)H → NAD(P)+] |
| NOS (nitric oxide synthase).– Location: membrane Isoforms: (e)NOS (endothelial): good (n)NOS (neuronal): good
(i)NOS (inducible-inflammatory): bad |
| O2- and nitric oxide (NO) are consumed in this process with the creation of reactive nitrogen
species (RNS). O2- + NO → ONOO- (peroxynitrite) + tyrosine → nitrotyrosine. Nitrotyrosine reflects redox stress and
leaves a measurable footprint. NO: the good; O2-: the bad; ONOO-: the ugly [42] |
| Nonenzymatic Antioxidants |
| URIC ACID |
| VITAMIN A, VITAMINC, andVITAMINE |
| THIOLS: Sulfhydryl (-SH) containing molecules. |
| ALBUMIN: Is an antioxidant due to thiol containing compounds. |
| APOPROTEINS: Ceruloplasmin and transferrin. Bind copper and iron in forms which cannot participate
in the Fenton reaction |
|
|
|
Hayden and Tyagi Nutrition Journal 2004 3:4 doi:10.1186/1475-2891-3-4 |
