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Pedrajas JR, et al.  (2010) Glutaredoxin participates in the reduction of peroxides by the mitochondrial 1-CYS peroxiredoxin in Saccharomyces cerevisiae. Antioxid Redox Signal 13(3):249-58

Abstract: The mechanism for regeneration of the active site "peroxidatic" cysteine in 1-Cys peroxiredoxins is a matter of debate. Saccharomyces cerevisiae Prx1 is a mitochondrial enzyme belonging to the 1-Cys Prx while Grx2 is involved in antioxidant defense and localizes at the mitochondria, so we hypothesized that it could be a perfect candidate to resolve the sulfenate in Prx1 with GSH. In vitro experiments with purified Prx1p and Grx2p demonstrate that Grx2, at concentrations below 1 microM, coupled to GSH is a very efficient thiolic intermediary for the reduction of the peroxidatic Cys in Prx1. Prx1 forms oligomeric aggregates natively, but depolymerizes down to a dimeric sate upon treatment with GSH. The catalytic cycle involves glutathionylation of dimeric Prx1 and deglutathionylation by Grx2. Dihydrolipoamide, a genuine mitochondrial dithiol, can efficiently substitute for GSH. The activity is highest at alkaline pH consistent with the conditions of active respiring mitochondria and the process is highly specific for 1-Cys Prx since Grx2 is totally inactive with human PRX-I, a typical 2-Cys Prx as opposed to the promiscuity of Trx. Our results suggest that while Trx is the reductant involved in the reduction of peroxides by 2-Cys-Prx, Grx might be the natural resolving partner of 1-Cys Prx through a monothiolic mechanism.

Status: Published

Type: Journal Article

PubMed ID: 20059400

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Pedrajas JR Padilla CA McDonagh BN Barcena JA Papers in SGD Colleagues in SGD PubMed Google Scholar

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