peroxiredoxin

Peroxiredoxins are a family of ubiquitous and highly conserved enzymes found in all organisms, from bacteria to humans. Their primary function is to reduce and detoxify reactive oxygen species (ROS), particularly hydrogen peroxide. These enzymes play a crucial role in cellular defense against oxidative stress, a condition that arises when the production of ROS overwhelms the cell's antioxidant capacity. Oxidative stress can damage vital cellular components like DNA, proteins, and lipids, leading to various diseases.

The catalytic mechanism of peroxiredoxins involves a conserved cysteine residue in their active site. This cysteine residue undergoes oxidation by hydrogen peroxide, forming a sulfenic acid intermediate. This intermediate is then reduced by another cysteine residue within the same molecule or on a different peroxiredoxin subunit, regenerating the active enzyme. Different types of peroxiredoxins exist, classified based on their structural organization and the mechanism of the resolving cysteine. For instance, 1-Cys peroxiredoxins utilize an intramolecular disulfide bond for reduction, while 2-Cys peroxiredoxins use an intermolecular disulfide bond.

Beyond their antioxidant role, peroxiredoxins are implicated in a variety of other cellular processes. These include regulating protein function through reversible oxidation of specific cysteine residues, acting as signaling molecules by modulating the activity of other proteins, and participating in cellular proliferation and differentiation. Dysregulation of peroxiredoxin activity has been linked to the pathogenesis of numerous diseases, including cancer, neurodegenerative disorders, and cardiovascular diseases. Their broad involvement in cellular health and disease makes them an active area of research.