An Interactive Jmol Tutorial about Peroxiredoxins

Peroxiredoxins (Prxs) are ubiquitous regulators of reactive oxygen species (ROS). Prxs primarily reduce H₂O₂ to water via their catalytic cysteine residues. Prxs often have secondary functions that are regulated in part by the redox state of their catalytic cysteines. Therefore, Prxs can sense and react to changes in cellular redox state to drive various response pathways. 

All Prxs have a Peroxidatic Cysteine (C_P).  Many also have a Resolving Cysteine (C_R) that will form a disulfide bond with a C_P after oxidation.

Basic Catalytic Cycle of a Prx:

1. Oxidation:  H₂O₂ is reduced at the C_P, resulting in oxidation of the thiol (Cys-SOH) and water.  The C_P can be overoxidized to sulfinic (-SO₂H) or sulfonic (-SO₃H) forms.

2. Resolving:  The C_P forms a disulfide bond with a C_R or a small molecule with a thiol group, such as glutathione (GSH).  This step distinguishes the three classes of Prxs.

3. Reduction/Recycling: The Prx cysteines are reduced by a thioredoxin, another GSH, or other redox partner.
   

Prxs are part of a larger redox signalling network in cells.

	From Thioredoxins	Page 1
	1-Cys Prx	Page 2
	Typical 2-Cys Prx	Page 3
	A- and B-interfaces	Page 4
	Prx3	Page 5