Article

Alterations in mitochondrial and cytosolic methionine sulfoxide reductase activity during cardiac ischemia and reperfusion.

Laboratoire de Biologie et Biochimie Cellulaire du Vieillissement, EA 3106/IFR 117, Université Paris 7-Denis Diderot, 2 place Jussieu, Tour 33-23, 1er étage, CC 7128, 75251 Paris Cedex 05, France.
Experimental Gerontology (impact factor: 3.74). 08/2006; 41(7):663-7. DOI:10.1016/j.exger.2006.03.011 pp.663-7
Source: PubMed

ABSTRACT During cardiac ischemia/reperfusion, proteins are targets of reactive oxygen species produced by the mitochondrial respiratory chain resulting in the accumulation of oxidatively modified protein. Sulfur-containing amino acids are among the most sensitive to oxidation. Certain cysteine and methionine oxidation products can be reversed back to their reduced form within proteins by specific repair enzymes. Oxidation of methionine in protein produces methionine-S-sulfoxide and methionine-R-sulfoxide that can be catalytically reduced by two stereospecific enzymes, methionine sulfoxide reductases A and B, respectively. Due to the importance of the methionine sulfoxide reductase system in the maintenance of protein structure and function during conditions of oxidative stress, the fate of this system during ischemia/reperfusion was investigated. Mitochondrial and cytosolic methionine sulfoxide reductase activities are decreased during ischemia and at early times of reperfusion, respectively. Partial recovery of enzyme activity was observed upon extended periods of reperfusion. Evidence indicates that loss in activity is not due to a decrease in the level of MsrA but may involve structural modification of the enzyme.

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    Article: Characterization of methionine oxidation and methionine sulfoxide reduction using methionine-rich cysteine-free proteins.
    Xinwen Liang, Alaattin Kaya, Yan Zhang, Dung Tien Le, Deame Hua, Vadim N Gladyshev
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    ABSTRACT: BACKGROUND: Methionine (Met) residues in proteins can be readily oxidized by reactive oxygen species to Met sulfoxide (MetO). MetO is a promising physiological marker of oxidative stress and its inefficient repair by MetO reductases (Msrs) has been linked to neurodegeneration and aging. Conventional methods of assaying MetO formation and reduction rely on chromatographic or mass spectrometry procedures, but the use of Met-rich proteins (MRPs) may offer a more streamlined alternative. RESULTS: We carried out a computational search of completely sequenced genomes for MRPs deficient in cysteine (Cys) residues and identified several proteins containing 20% or more Met residues. We used these MRPs to examine Met oxidation and MetO reduction by in-gel shift assays and immunoblot assays with antibodies generated against various oxidized MRPs. The oxidation of Cys-free MRPs by hydrogen peroxide could be conveniently monitored by SDS-PAGE and was specific for Met, as evidenced by quantitative reduction of these proteins with Msrs in DTT- and thioredoxin-dependent assays. We found that hypochlorite was especially efficient in oxidizing MRPs. Finally, we further developed a procedure wherein antibodies made against oxidized MRPs were isolated on affinity resins containing same or other oxidized or reduced MRPs. This procedure yielded reagents specific for MetO in these proteins, but proved to be ineffective in developing antibodies with broad MetO specificity. CONCLUSION: Our data show that MRPs provide a convenient tool for characterization of Met oxidation, MetO reduction and Msr activities, and could be used for various aspects of redox biology involving reversible Met oxidation.
    BMC Biochemistry 10/2012; 13(1):21. · 1.99 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

Certain cysteine
 
cytosolic methionine sulfoxide reductase activities
 
enzyme activity
 
enzymes
 
methionine oxidation products
 
methionine sulfoxide reductase system
 
methionine sulfoxide reductases
 
methionine-R-sulfoxide
 
methionine-S-sulfoxide
 
Mitochondrial
 
mitochondrial respiratory chain
 
Oxidation
 
oxidative stress
 
oxidatively
 
protein structure
 
reduced form
 
sensitive
 
stereospecific enzymes
 
Sulfur-containing amino acids
 
times