The peroxiredoxin (PRX) family comprises six antioxidant proteins, PRX I, II, III,
IV, V and VI, which protect cells from reactive oxygen species (ROS) by preventing
the metal-catalyzed oxidation of enzymes. The PRX proteins primarily
utilize thioredoxin as the electron donor for antioxidation, although they are
fairly promiscuous with regard to the hydroperoxide substrate. In addition to
protection from ROS, peroxiredoxins are also involved in cell proliferation, differentiation
and gene expression. PRX I, II, IV and VI show diffuse cytoplasmic
localization, while PRX III and V exhibit distinct mitochondrial localization.
The human PRX I gene encodes a protein that is expressed in several tissues,
including liver, kidney, testis, lung and nervous system. PRX II is expressed in
testis, while PRX III shows expression in lung. PRX I, II and III are overexpressed
in breast cancer and may be involved in its development or progression.
Upregulated protein levels of PRX I and II in Alzheimer’s disease (AD)
and Down syndrome (DS) indicate the involvement of PRX I and II in their
pathogenesis.