Reducing agent, specific for disulfidesTris(2-carboxyethyl)phosphine hydrochloride is widely used as a reducing agent to reduce disulfide bonds in proteins and trans-4,5-dihydroxy-1,2-dithiane. It is involved in the reduction of sulfoxides, sulfonyl chlorides, N-oxides, and azides. It plays an important role in the tissue homogenization process for RNA isolation. It acts as a chelating agent and forms complexes with various heavy metal ions such as Zn(II), Cd(II), Pb(II), and Ni(II). Furthermore, it is useful in the labeling of cysteine residues with maleimides.