Identification of intact protein thiosulfinate intermediate in the reduction of cysteine sulfinic acid in peroxiredoxin by human sulfiredoxin.

ABSTRACT: The reversible oxidation of the active site cysteine in typical 2-Cys peroxiredoxins (Prx) to sulfinic acid during oxidative stress plays an important role in peroxide-mediated cell signaling. The catalytic retroreduction of Prx-SO(2)(-) by sulfiredoxin (Srx) has been proposed to proceed through two novel reaction intermediates, a sulfinic phosphoryl ester and protein-based thiosulfinate. Two scenarios for the repair mechanism have been suggested that differ in the second step of the reaction. The attack of Srx or GSH on the Prx-SO(2)PO(3)(2-) intermediate would result in either the formation of Prx-Cys-S(=O)-S-Cys-Srx or the formation of Prx-Cys-S(=O)-S-G thiosulfinates, respectively. To elucidate the mechanism of Prx repair, we monitored the reduction of human PrxII-SO(2)(-) using rapid

SUBMITTER: Jonsson TJ 

PROVIDER: S-EPMC2517003 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature