dTT

Dithiothreitol (DTT) is a small-molecule reducing agent widely used in biochemistry and molecular biology. It functions to break disulfide bonds in proteins and other biomolecules, converting cystine residues to cysteine. In its oxidized form, DTT forms a cyclic disulfide. DTT is soluble in water and is typically employed in millimolar concentrations in buffered aqueous solutions.

Chemically, DTT contains two thiol groups that donate electrons to disulfide bonds. As disulfides are reduced, DTT itself is oxidized to its cyclic disulfide form. The redox activity of DTT is exploited to maintain proteins in a reduced state during purification, characterization, and various assay workflows. It is commonly selected for its robust reducing power and compatibility with many biochemical protocols.

Common uses include preparing protein samples for electrophoresis (such as SDS-PAGE and Western blotting), maintaining enzyme activity by preventing disulfide bond formation, and preserving reduced cofactors during extraction and purification. DTT is also employed in some nucleic acid protocols to minimize oxidative damage. Typical working concentrations range from 1 to 10 mM, while stock solutions are often prepared at 0.1–1 M and stored frozen to limit oxidation.

Handling and storage require care because DTT is prone to oxidation in solution. Prepare fresh working solutions as needed, keep solutions cold, and aliquot stocks to minimize repeated freeze-thaw cycles. DTT is hazardous if inhaled, ingested, or in contact with skin or eyes; handle with appropriate personal protective equipment and dispose of waste according to institutional guidelines.