Peptide methionine sulfoxide reductase: Biochemistry and physiological role

The oxidation of methionine to methionine sulfoxide both in vivo and in vit ro can lead to the loss of biological activity in a variety of proteins. Th is loss of activity can be reversed by an enzyme called methionine sulfoxid e reductase. The gene for this enzyme has been cloned and sequenced from a variety of prokaryotic and eukaryotic cells, and the deduced amino acid seq uence is very highly conserved. The mechanism of action of the bovine enzym e has been shown to involve a critical cysteine residue located at position 72 of the protein. In addition to its role as a "repair" enzyme, other evi dence suggests that the enzyme may be involved in bacterial adherence and r egulation of protein activity. (C) 2001 John Wiley & Sons, Inc.