1M Dithiothreitol is a ready-to-use 1 M solution of dithiothreitol (DTT), a thiol reducing agent, in purified water. Each lot is tested for DNase and RNase activity. The 1 mL single-use tubes avoid repeated freeze–thaw and air exposure.

It is commonly used to reduce protein disulfides for SDS-PAGE, mass spectrometry, and enzyme assays, and to keep cysteine thiols reduced during protein handling. In antibody conjugation, it partially reduces interchain disulfides for maleimide–thiol coupling; remove it by buffer exchange before adding linker-payload. Store frozen and thaw just before use, since DTT oxidizes in air.