Fig. 2.

Reactions of members of the DSOR family. (A) Steps resulting in the reduction of the redox-active cysteine disulfide for all DSOR enzymes; (B) steps resulting in reduction of a substrate with an oxidized disulfide bond, as illustrated for glutathione reductase; (C) steps resulting in reduction of the thioether bond of 2-KPC in 2-KPCC, resulting in the production of enolacetone, which undergoes carboxylation to form acetoacetate. Note that the reduced flavin cysteine is shown in the thiol rather than as the thiolate form for 2-KPCC for reasons described in the paper.