1,4-Dithiothreitol (DTT) is used as a protecting agent in chemical synthesis.
DTT is an exceptionally strong reducing agent, due to its high conformational propensity to form a six-membered ring with an internal disulfide bond when oxidised. DTT is commonly used to reduce the disulfide bonds of protein and peptides.
As an oxidising agent, no mixed-disulfide species are developed.