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 Jurkat T-lymphoma cells. Although the local cellular environment could influence susceptibility, purified Prx 3 was also more resistant to hyperoxidation, suggesting that despite having C-terminal motifs similar to sensitive eukaryote Prxs, other structural features must contribute to the innate resilience of Prx 3 to hyperoxidation.
Mitochondrial peroxiredoxin 3 is more resilient to hyperoxidation than cytoplasmic peroxiredoxins
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Andrew G. Cox, Andree G. Pearson, Juliet M. Pullar, Thomas J. Jönsson, W. Todd Lowther, Christine C. Winterbourn, Mark B. Hampton; Mitochondrial peroxiredoxin 3 is more resilient to hyperoxidation than cytoplasmic peroxiredoxins. Biochem J 1 July 2009; 421 (1): 51–58. doi: https://doi.org/10.1042/BJ20090242
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