FIGURE 1.

Comparison of the proposed sulfinic acid reduction mechanisms of Srx. Path 1 represents the mechanism originally proposed by Biteau et al. (10). Path 2 incorporates modifications to the reaction pathway as suggested by Jeong et al. (21). Step 1 involves the formation of the sulfinic acid phosphoryl ester intermediate. In Step 2 of the reaction, the addition of a thiol group leads to the formation of different thiosulfinate intermediates. This intermediate is subsequently resolved by additional thiols in Step 3. The thiol RSH could represent GSH or Trx.