DTT stands for DL Dithiothreitol, also known as dithiothreitol in Chinese. The molecular formula is C4H10O2S2, with a molecular weight of 154.25. Commonly used reducing agents have antioxidant properties. Compared with mercaptoethanol, DTT has similar effects, but its irritating odor is much smaller and its toxicity is much lower. Moreover, when the concentration of DTT is 7 times lower than that of mercaptoethanol, the two effects are similar.

The role of DTT (dithiothreose):

DTT stands for DL Dithiothreitol, also known as dithiothreitol in Chinese. The molecular formula is C4H10O2S2, with a molecular weight of 154.25. Commonly used reducing agents have antioxidant properties. Compared with mercaptoethanol, DTT has similar effects, but its irritating odor is much smaller and its toxicity is much lower. Moreover, when the concentration of DTT is 7 times lower than that of mercaptoethanol, the two effects are similar.

The characteristics of DTT:

DTT is a strong reducing agent, and its reducibility 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.

Due to its susceptibility to air oxidation, DTT has poor stability; But cryopreservation or treatment in inert gas can extend its service life. Due to the low nucleophilicity of protonated sulfur, the effective reducibility of DTT decreases with the decrease of pH value; Tris (2-carboxymethyl) hydrochloride HCl (TCEP hydrochloride) can be used as a substitute for DTT under low pH conditions and is also more stable than DTT.

Preparation method for 1mol/L dithiothreose (DTT) solution:

Dissolve 3.09g DTT in 20ml 0.01mol/L sodium acetate solution (pH 5.2), filter and sterilize, then divide into 1ml small portions and store at -20 ℃.

[Note] DTT or solutions containing DTT should not be subjected to high-pressure treatment.

The role of DTT:

One of the uses of DTT is as a reducing agent and deprotective agent for thiolated DNA. The sulfur atoms at the end of thiolated DNA tend to form dimers in solution, especially in the presence of oxygen. This dimerization greatly reduces the efficiency of some coupling reaction experiments, such as DNA fixation in biosensors; Adding DTT to DNA solution and removing it after a period of reaction can reduce DNA dimerization.

DTT is also commonly used for the reduction of disulfide bonds in proteins, which can be used to prevent the formation of intramolecular or intermolecular disulfide bonds between cysteine in proteins. However, DTT is often unable to reduce disulfide bonds embedded within the protein structure (out of the reach of solvents). The reduction of such disulfide bonds often requires denaturation of the protein (high-temperature heating or addition of denaturants such as 6M guanidine hydrochloride, 8M urea, or 1% SDS). On the contrary, based on the different reduction rates of disulfide bonds in the presence of DTT, the depth of its encapsulation can be determined.