Dithiothreitol Introduction and Application Dithiothreitol (DTT) is a small molecule organic reducing agent with the chemical formula C4H10O2S2. In its reduced state, Dithiothreitol (DTT) is a linear molecule, and after oxidation, Dithiothreitol (DTT) becomes a six membered cyclic structure containing disulfide bonds. The name dithiothreitol is derived from threose (a four carbon monosaccharide). The isomer of DTT is dithioerythritol (DTE), which is the C3 isomer of DTT. One of the uses of DTT is as a reducing agent and deprotection agent for thiolated DNA. The thiolated end sulfur atoms of 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 residues in proteins. However, DTT often cannot reduce disulfide bonds embedded within protein structures (inaccessible to solvents), and the reduction of such disulfide bonds often requires denaturation of the protein (high-temperature heating or the addition of denaturing agents 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 embedding can be determined.
