P-127 - Role of peroxiredoxin 2 in erythrocyte antioxidant defense: peroxidase and chaperone

Abstract

We aimed to study the role of Peroxiredoxin 2 (Prx2) in the erythrocyte antioxidant defense. We performed in vitro assays (n= 3) using healthy erythrocytes, with and without inhibiting Prx2 (Conoidin A) or methemoglobin (metHb) formation (carbon monoxide saturation). We assessed Prx2 amount in cytosol and membrane by western-blot and membrane bound hemoglobin (MBH) by spectroscopy. In steady state (no inhibition) conditions, Prx2 presented a typical peroxidase behavior in the cytosol and small amounts were detected in the membrane. When metHb formation was prevented, Prx2 was observed in the monomeric (active) form in the cytosol and none in the membrane. When Prx2 was inhibited, we found cytosol's Prx2 mainly in the inactive (dimer) form and high amount bound to the membrane; in this assay condition, we also observed the lowest value of MBH. Our results show that inhibition of Prx2 leads to an increase in its membrane linkage, and to a decrease in MBH, as they share the same membrane-binding site. We also found that when Hb molecule is in risk (CO), Prx2 specifically protects it, shifting its action from peroxidase to chaperone.