Augmented expression of peroxiredoxin VI in rat lung and kidney after birth implies an antioxidative role

A family of proteins with thioredoxin (TRx)-dependent peroxidase activity, referred to as peroxiredoxins (PRx), has been identified in many species. T he sixth member of this family, PRxVI, contains only one conserved cysteine residue, while other members contain additional cysteines. We have isolate d a cDNA for rat PRxVI and constructed a large scale baculovirus system to produce the recombinant protein. The protein was purified by a simple two-s tep procedure utilizing ion-exchange and gel-filtration chromatography. The purified PRxVI exhibited a low level of glutathione-dependent peroxidase b ut not TRx-dependent activity. PRxVI expression was the highest in lung, fo llowed by brain, kidney, heart, testis, etc. as judged by Northern and West ern blot analyses using a rabbit antibody to the purified PRxVI. Immunohist ochemical analyses showed strong staining in the epithelium of the bronchus and bronchioles in lung and in the epithelial cells of kidney tubules. In addition, Sertoli cells in testis and islet of Langerhans cells in pancreas were strongly stained. The developmental changes of PRxVI expression in lu ng and kidney were low in the prenatal stage but induced postnatally. Moreo ver, intraperitoneal administration of chloroform induced PRxVI mRNA in kid ney. When the distribution and the induced expression of PRxVI under condit ions of oxidative stress are considered, a physiological role of it as an a ntioxidative enzyme is indicated.