Methionine oxidation and reduction in proteins

Background: Cysteine and methionine are the two sulfur containing amino acids in proteins. While the roles of protein-bound cysteinyl residues as endogenous antioxidants are well appreciated, those of methionine remain largely unexplored.

Scope: We summarize the key roles of methionine residues in proteins.

Major conclusion: Recent studies establish that cysteine and methionine have remarkably similar functions.

General significance: Both cysteine and methionine serve as important cellular antioxidants, stabilize the structure of proteins, and can act as regulatory switches through reversible oxidation and reduction. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.