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Oxidation of Methionine in Proteins: Roles in Antioxidant Defense and Cellular Regulation
Author(s) -
Levine Rodney L.,
Moskovitz Jackob,
Stadtman Earl R.
Publication year - 2000
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/713803735
Subject(s) - methionine sulfoxide , methionine , methionine sulfoxide reductase , cysteine , biochemistry , sulfoxide , chemistry , antioxidant , amino acid , cysteine metabolism , oxidative phosphorylation , msra , residue (chemistry) , enzyme , organic chemistry
The roles of methionine residues in proteins have not been well defined, but a review of available studies leads to the conclusion that methionine, like cysteine, functions as an antioxidant and as a key component of a system for regulation of cellular metabolism. Methionine is readily oxidized to methionine sulfoxide by many reactive species. The oxidation of surface exposed methionines thus serves to protect other functionally essential residues from oxidative damage. Methionine sulfoxide reductases have the potential to reduce the residue back to methionine, increasing the scavenging efficiency of the system. Reversible covalent modification of amino acids in proteins provides the mechanistic basis for most systems of cellular regulation. Interconversion of methionine and methionine sulfoxide can function to regulate the biological activity of proteins, through alteration in catalytic efficiency and through modulation of the surface hydrophobicity of the protein.