DL-Dithiothreitol is a very strong reducing agent whose reductibility is largely due to the conformational stability of its oxidized six-membered ring (containing disulfide bonds). Its redox potential is -0.33 volts at pH 7. The reduction of a typical disulfide bond by dithiothreitol consists of a two-step continuous thiol-disulfide exchange reaction:
Among them, the intermediate state formed by the first step reaction is very unstable, because the second sulfhydryl group on the DL-Dithiothreitol tends to be linked to the oxidized sulfur atom, so that the intermediate state is quickly converted into the cyclic oxidation of DL-Dithiothreitol. Structure, thereby completing the reduction of the disulfide bond.
The reducing power of DL-Dithiothreitol is affected by the pH value and can only be reduced when the pH is greater than 7. This is because only the proton-depleted thiolate anion (-S-) is reactive, and the mercaptan (-SH) is absent; and the sulfhydryl has a pKa of typically -8.3.
DL-Dithiothreitol is a strong reducing agent
