Insulin reduction by wild type and mutant BC3987.

In the insulin reduction assay, the rate of insulin disulfide reduction by DTT is enhanced using 10 µM thioredoxin as a catalyst. The wild type BX3987 thioredoxin (▪) is more efficient than the T8A mutant (•). The control experiment without thioredoxin shows that the uncatalyzed reaction with DTT is very slow (▴). The concentration of insulin and DTT used in the assay was 160 µM and 1 mM, respectively. The turbidity of the assay solution was monitored at 580 nm (light scattering).