FIGURE 5.
Conversion of (GspS)2 to GSH and Spd by the Gsp amidase/GSH reductase couple. A, a MALDI-TOF spectrum that shows the molecular weights of the hydrolysis products after (GspS)2 was treated with GspSA for 0 min (top), 10 min (middle), or 4 h (bottom). GSSG was the end product. B, the Gsp amidase/GSH reductase coupled assay. (GspS)2 cannot be reduced by GSH reductase alone (■), but it is reduced when both GspSA and GSH reductase are present (▵). GSSG plus GSH reductase served as the positive control (●). GSH reductase alone served as the negative control (○). C, reaction scheme for the enzymatic conversion of (GspS)2 to GSH and Spd by the Gsp amidase/GSH reductase couple.