期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：11
页码：3780-3785
DOI：10.1073/pnas.0400181101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：1-cys peroxiredoxin (1-cysPrx), a member of the peroxiredoxin superfamily, can protect cells against membrane oxidation through glutathione (GSH)-dependent reduction of phospholipid hydroperoxides to corresponding alcohols. However, purified native or recombinant enzyme in vitro generally lacks GSH peroxidase (GPx) activity because of oxidation of its single conserved cysteine. Reduction of the resultant oxidized cysteine is difficult because of its protected location within the homodimer formed by the oxidized protein monomers. Partial purification of 1-cysPrx from bovine lung revealed the presence of {pi}GST in an active preparation, while purification to homogeneity yielded enzyme that inactivated with time. We show that heterodimerization of 1-cysPrx with GSH-saturated {pi}GST results in glutathionylation of the oxidized cysteine in 1-cysPrx followed by subsequent spontaneous reduction of the mixed disulfide and restoration of enzymatic activity. Maximum activation of 1-cysPrx occurred with a 1:1 molar ratio of GSH-saturated {pi}GST and a 2:1 molar ratio of GSH to 1-cysPrx. Liposome-mediated delivery of oxidized recombinant enzyme into NCI-H441 cells that lack 1-cysPrx but express {pi}GST resulted in 1-cysPrx activation, whereas activation in MCF7 cells required co-delivery of {pi}GST. Our data indicate a physiological mechanism for glutathionylation of the oxidized catalytic cysteine of 1-cysPrx by its heterodimerization with {pi}GST followed by its GSH-mediated reduction and enzyme activation.
