Mammalian peroxiredoxîn isoforms can reduce hydrogen peroxide generated in response to growth factors and tumor necrosis factor-o

Mammalian tissues express three immunologirally distinct Prx proteins (Prx I. II. and III), which are the products of distinct genes. With the use of recorn binant proteins. Prx I, II. and III all have now been shown to possess peroxidase activity and 1 o relv on Trx as a source of reducing equivalents for the reduction of I-4O;. Prx I and II are rytosolic proteins, whereas Prx III is localized in mitochondria. Transient ovcre.x pression of Prx I or II in cultured cells showed that they weie able to eliminate the intracellular H₂U2 gpnerated in response to growth factors. Moreover, the activation of nuclear factor K B(NF-:B} induced by extraroltularlv added IIiQ- or tumor necrosis factor-alpha was blocked by overproduction of Prxll. These results suggest that, together with glutatlnone peroxidase and catalase, Prx enzymes likely pi ay an important role in eliminating peroxides generated during metabolism. In addition. Prx I and II might participate in the signaling cascades of growth factors and TNF-o by regulating the intraocular foncent ratio of \\-402.