The results of this study are applicable to understanding the requirements for MsrA function on a wide range of met oxidized target proteins and disease states since methionine is one of the most oxidizable protein amino acids [13] and PMSO accumulation is associated with a broad range of age-related human disorders associated with methionine oxidation including Alzheimer's disease, Parkinson's disease, respiratory distress syndrome, emphysema, and reperfusion injury [1], [2], [3], [4], [5], [7], [14], [15]. This evidence concerns the gene MSRA and early-onset autosomal dominant Alzheimer disease.