Methionine oxidation

Methionine oxidation is the oxidation of the sulfur of the amino acid methionine resulting in methionine sulfoxide or methionine sulfone. The sulfur-containing amino acids methionine and cysteine are more easily oxidized than the other amino acids.[1] Unlike oxidation of other amino acids, the oxidation of methionine can be reversed by enzymatic action, specifically by enzymes in the methionine sulfoxide reductase family of enzymes. The three known methionine sulfoxide reductases are MsrA, MsrB, and fRmsr.[1] Oxidation of methionine results in a mixture of the two diastereomers methionine-S-sulfoxide and methionine-R-sulfoxide, which are reduced by MsrA and MsrB, respectively.[2] MsrA can reduce both free and protein-based methionine-S-sulfoxide, whereas MsrB is specific for protein-based methionine-R-sulfoxide. fRmsr, however, catalyzes the reduction of free methionine-R-sulfoxide.[1] Thioredoxin serves to recycle by reduction some of the methionine sulfoxide reductase family of enzymes, whereas others can be reduced by metallothionein.[3]

Methionine sulfoxide increases with age in body tissues, which is believed to contribute to ageing.[4][5] Transgenic Drosophila (fruit flies) that overexpress methionine sulfoxide reductase show extended lifespan.[6]

See also

References

  1. ^ a b c Lee BC, Dikiy A, Kim HY, Gladyshev VN (2009). "Functions and evolution of selenoprotein methionine sulfoxide reductases". BIOCHEMICA ET BIOPHYSICA ACTA 1790 (11): 1471-1477. PMID 19406207. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3062201/. 
  2. ^ Kim HY, Gladyshev VN (2004). "Methionine sulfoxide reduction in mammals: characterization of methionine-R-sulfoxide reductases". MOLECULAR BIOLOGY OF THE CELL 15 (3): 1055-1064. PMID 14699060. http://www.molbiolcell.org/content/15/3/1055.long. 
  3. ^ Sagher D, Brunell D, Hejtmancik JF, Kantorow M, Brot N, Weissbach H (2006). "Thionein can serve as a reducing agent for the methionine sulfoxide reductases". Proceedings of the National Academy of Sciences of the United States of America 103 (23): 8656-8661. PMID 16735467. http://www.pnas.org/content/103/23/8656.long. 
  4. ^ Stadtman ER, Van Remmen H, Richardson A, Wehr NB, Levine RL (2005). "Methionine oxidation and aging". BIOCHEMICA ET BIOPHYSICA ACTA 1703 (2): 135-140. PMID 15680221. 
  5. ^ Shringarpure R, Davies KJ (2002). "Protein turnover by the proteasome in aging and disease". FREE RADICAL BIOLOGY & MEDICINE 32 (11): 1084-1089. PMID 12031893. 
  6. ^ Ruan H, Tang XD, Chen ML, Joiner ML, Sun G, Brot N, Weissbach H, Heinemann SH, Iverson L, Wu CF, Hoshi T (2002). "High-quality life extension by the enzyme peptide methionine sulfoxide reductase". Proceedings of the National Academy of Sciences of the United States of America 99 (5): 2748-2753. PMID 11867705. http://www.pnas.org/content/99/5/2748.full. 

External links