Mitochondrial peroxiredoxin 3 is more resilient to hyperoxidation than cytoplasmic peroxiredoxins

Abstract

The Prxs (peroxiredoxins) are a family of cysteine-dependent peroxidases that decompose hydrogen peroxide. Prxs become hyperoxidized when a sulfenic acid formed during the catalytic cycle reacts with hydrogen peroxide. In the present study, Western blot methodology was developed to quantify hyperoxidation of individual 2-Cys Prxs in cells. It revealed that Prx 1 and 2 were hyperoxidized at lower doses of hydrogen peroxide than would be predicted from in vitro data, suggesting intracellular factors that promote hyperoxidation. In contrast, mitochondrial Prx 3 was considerably more resistant to hyperoxidation. The concentration of Prx 3 was estimated at 125 μM in the mitochondrial matrix of Ju..