Methionine Sulfoxide Reductase A (MSRA)

Peptide methionine sulfoxide reductase is ubiquitous and highly conserved. It carries out the enzymatic reduction of methionine sulfoxide to methionine. Human and animal studies have shown the highest levels of expression in kidney and nervous tissue. MSRA mRNA is highly expressed in rat and human kidney, but to a lesser extent in other rat tissues. The highest specific activity of the mammalian MSRA enzyme was found in cell-free extracts prepared from rat kidney and human neutrophils. Neutrophils and macrophages are known to produce reactive oxygen species during a respiratory burst that kill invading bacteria during phagocytosis. It is suggested that MSRA functions to repair oxidative damage to proteins that may occur during oxidative bursts or other situations where reactive oxygen radicals exist.