Protein reducing agents dithiothreitol and tris(2-carboxyethyl)phosphine anodic oxidation

Protein reducing agents dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP) are crucial to disrupt disulfide bonds for qualitative and quantitative analysis in proteomics. Protein bond disruption is very important for analyzing proteins as single subunits. The electrochemical oxidation mechanism of DTT and TCEP was investigated using cyclic and differential pulse voltammetry over a wide pH range on a glassy carbon electrode. The oxidation mechanism of both compounds is irreversible, pH-dependent and proceeds in a single step. The anodic oxidation of DTT is associated with the oxidation of the sulfhydryl group with lowest pKa, while the anodic oxidation of TCEP is associated with the oxidation of the phosphine group in the molecule. The diffusion coefficients of DTT and TCEP were calculated, and the redox mechanisms are proposed.