Peroxiredoxin Ⅱ(prxⅡ),a cytosolic form of the anti-oxidant peroxiredoxin family,was recently found to be decreased in failing human hearts.Interestingly,in hyperdynamic hearts of two genetically modified mouse models with: a)phospholamban ablation; and b)overexpression of the active inhibitor-1 of protein phosphatase 1,the levels of this cellular peroxidase(prxⅡ)were markedly increased.