Figure 1.

Catalytic cycle of peroxide reduction by 2‐Cys Prx. (1) Oxidation. Reaction of Prx peroxidatic cysteine C_P with peroxide substrate yield the sulfenic acid. In brackets is represented the dynamic equilibrium between the LU and the FF structural conformations. (2) Resolution. Disulfide formation between C_P and C_R. (3) Reduction by thioredoxin to complete the cycle. (4) Hyperoxidation. Reaction of the sulfenic acid of C_P with H₂O₂, yielding a sulfinic acid which inactivates the enzyme. For each step, the associated rate constant is represented.