Heterogeneity and function of mammalian MSRs: enzymes for repair, protection and regulation.
Methionine sulfoxide, the physiologically relevant oxidation product of methionine, is enzymatically reduced by peptide methionine sulfoxide reductases (MSRs). Two distinct classes of these enzymes, MSRA and MSRB, which selectively reduce the two methionine sulfoxide epimers, methionine-S-sulfoxide and methionine-R-sulfoxide, respectively, are found in virtually all organisms. Mammals typically possess only one gene encoding MSRA, but at least three genes encoding MSRBs. These MSRs show distinct tissue- and subcellular expression patterns and may play specific functional roles. Susceptibility of some ion channels to reversible methionine oxidation suggests that MSRs have a regulatory role in cellular excitability. Some--if not all--MSRs protect cells and organisms against a variety of oxidative stress episodes, including those by hypoxia and reperfusion, and play a modulatory role in lifespan determination. More MSR-dependent physiological phenomena await to be discovered.
Hansel
Alfred
A
Molecular and Cellular Biophysics, Medical Faculty of the Friedrich Schiller University Jena, Drackendorfer Strasse 1, D-07747 Jena, Germany.
Heinemann
Stefan H
SH
Hoshi
Toshinori
T
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D008322:Mammals; D051150:Methionine Sulfoxide Reductases; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism*; D017382:Reactive Oxygen Species
D017931:DNA Primers; D017382:Reactive Oxygen Species; D010088:Oxidoreductases; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase