Hypochlorous acid (HOCl) is a powerful oxidizing and chlorinating agent produced by the neutrophil enzyme myeloperoxidase. The antioxidant defenses of freshly prepared human plasma against HOCl/OCl- were explored. Addition of HOCl/OCl- to plasma caused rapid oxidation of ascorbic add and thiol (-SH) groups but not of uric acid. Plasma -SH groups (which are known to be largely located on albumin) were quantitatively the most important scavenger of HOCl/OCl-, but adding extra ascorbate to plasma caused this molecule to have a more important scavenging role against HOCl/OCl-. Added HOCl/OCl- produced no detectable lipid peroxidation in plasma or depletion of lipid-soluble antioxidants (α-tocopherol or ubiquinol10). No evidence of oxidative damage to protein amino acid residues (other than -SH) was detected by the carbonyl assay. It seems that -SH groups are a major target of attack by HOCl/OCl- in vivo, and plasma albumin may be an important protective antioxidant. Ascorbic acid might also play a protective role, especially in individuals supplemented with this vitamin. Ascorbate might also be important in extracellular fluids with low albumin concentrations such as synovial, respiratory tract lining, and cerebrospinal fluids.
|Original language||English (US)|
|Number of pages||6|
|Journal||The Journal of Laboratory and Clinical Medicine|
|State||Published - 1993|
ASJC Scopus subject areas
- Pathology and Forensic Medicine