DL Dithiothreitol (DTT for short) is a small molecule organic reductant, which is mainly used in the field of biotechnology as a protein cleavage reagent. DTT is a strong reducing agent, and its reducibility is largely due to the conformational stability of its oxidized six membered ring (containing disulfide bond). One of the uses of DTT is as a reductant and deprotector of thiolated DNA.

Dithiothreitol has antioxidant effect. It can protect the reducing groups on the enzyme molecules, maintain the reducing environment, and stabilize the enzyme activity. DTT also contains some RNA enzyme inhibitors, which can inhibit the activity of RNA enzyme. It has the similar effect of mercaptoethanol (dimercaptoethanol), but the irritating smell of DTT is much smaller and the toxicity is much lower than mercaptoethanol. It is a protein binding agent