What substance is used to reduce disulfide bonds in proteins?

Dithiothreitol (DTT) is a reducing agent specifically used to break disulfide bonds in proteins. Disulfide bonds are covalent linkages formed between the sulfhydryl groups of cysteine residues, playing a crucial role in stabilizing the three-dimensional structure of proteins. By donating electrons, DTT effectively cleaves these bonds, thereby facilitating the unfolding of proteins or allowing for the analysis of their individual components.

DTT is particularly valued in biochemical and molecular biology applications because it is soluble in water and does not interfere with many downstream processes. It helps maintain proteins in a reduced state, which is essential during various experimental procedures such as protein purification, gel electrophoresis, or when analyzing protein interactions.

In contrast, the other substances listed have different functions. Iodoacetate is known for inhibiting enzymatic activity by modifying cysteine residues but does not reduce disulfide bonds. FDNB (factorial dinitrobenzene) is primarily used as a labeling reagent for amino groups in proteins and does not target disulfide bonds. Glutathione, while it can act as an antioxidant and is involved in redox reactions, is more commonly used to maintain a reducing environment, but it is not as direct