ISSN:
1573-904X
Keywords:
methionine
;
methionine sulfoxide
;
free radicals
;
ascorbate
;
dithiothreitol
;
catalase
;
superoxide dismutase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract In the presence of oxygen, Fe(III), and an appropriate electron donor (e.g. ascorbic acid, dithiothreitol), the oxidation of methionine residues to methionine sulfoxides in small model peptides can be induced. It is shown in this study that these oxidations can be retarded by catalase in a pH-dependent manner, by some hydroxyl radical scavengers, and by azide. In contrast, superoxide dismutase has only a minimal effect, indicating that the superoxide radical does not contribute significantly to the oxidation of the methionine residue. The experimental results can be interpreted by invoking hydrogen peroxide as the major oxidizing species at pH ≤ 7, whereas the involvement of free hydroxyl radicals seems to be negligible. Other reactive oxygen intermediates such as iron-bound hydroperoxy, or site-specifically generated reactive oxygen species may be actively involved in the oxidation of methionine residues at pH 〉 7.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1016240115675
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