US EPA

99319 

Journal Article 

Reactive nitrogen species derived activation of rat liver microsomal glutathione S-transferase 

Imaizumi, N; Miyagi, S; Aniya, Y 

2006 

1 

Life Sciences
ISSN: 0024-3205
EISSN: 1879-0631 

78 

26 

2998-3006 

English 

16386761 

10.1016/j.lfs.2005.11.026 

WOS:000237749300003 

The effect of reactive nitrogen species on rat liver microsomal glutathione S-transferase (MGST1) was investigated using microsomes and purified MGST1. When microsomes or the purified enzyme were incubated with peroxynitrite (ONOO(-)), the GST activity was increased to 2.5-6.5 fold in concentration-dependent manner and a small amount of the MGST1 dimer was detected. MGST1 activity was increased by ONOO(-) in the presence of high amounts of reducing agents including glutathione (GSH) and the activities increased by ONOO(-) or ONOO(-) plus GSH treatment were decreased by 30-40% by further incubation with dithiothreitol (DTT, reducing disulfide) or by sodium arsenite (reducing sulfenic acid). Furthermore, GSH was detected by HPLC from the MGST1 which was incubated with ONOO(-) plus GSH or S-nitrosoglutathione followed by DTT treatment. In addition, the MGST1 activity increased by nitric oxide (NO) donors such as S-nitrosoglutathione, S-nitrosocysteine or the non-thiol NO donor 1-hydroxy-2-oxo-3 (3-aminopropyl)-3-isopropyl was restored by the DTT treatment. Since DTT can reduce S-nitrosothiol and disulfide bond to thiol, S-nitrosylation and a mixed disulfide bond formation of MGST1 were suggested. Thus, it was demonstrated that MGST1 is activated by reactive nitrogen species through a forming dimeric protein, mixed disulfide bond, nitrosylation and sulfenic acid. 

Animals; Blotting, Western; Dithiothreitol/pharmacology; Glutathione Transferase/*metabolism; Male; Microsomes, Liver/*metabolism; Nitric Oxide Donors/pharmacology; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Reactive Nitrogen Species/*metabolism; S-Nitrosoglutathione/metabolism; Sulfhydryl Compounds/metabolism; Sulfhydryl Reagents/pharmacology