ADCs Toxins, Used in molecular biology. DTT preserves proteins of interiors of cells in their functional form by avoiding the oxidation of Sulfhidril-groups (SH-) into disulifidbridges through atmospheric oxygen. On the other hand the convolution of proteins whose structure is stabilised by disulfidbridges may be destroyed by their reduction. It is an important reagent in the course of SDS-PAGE and Western-Blotting respectively.