For the last 18 years, AG Scientific has been a leading supplier of DTT, dithiothreitol, historically known as Cleland’s Reagent. We offer a range of catalog sizes, as well as, multi-kilogram quantities for bulk applications. Additionally, we provide a full service of bottling, sterile formulations, custom packaging, as well as, comprehensive private labeling capabilities.

dtt_dithiothreitol_chemical structure
DTT Chemical Structure

DTT, is a product for which we often get questions on the following: solution preparation, storage, stability, handling, trouble shooting, how to avoid common mistakes.... Here are the most Frequently Asked Questions (FAQS) we have received from our customers and the appropriate answers. A Material and Safety (MSDS) document link is also available for download.


ANSWER: DTT is a protective agent for reducing –S-S TO SH groups. Used as a strong reducing agent for proteins and enzymes. Enhances DNA polymerase activity.

  • QUESTION: Are there alternative names?
    ANSWER: Yes, DTT is also known as Dithiothreitol or originally as Cleland’s reagent after discover, W.W. Cleland, University of Wisconsin.

QUESTION: What is the stability of DTT?
ANSWER: When refrigerated 2-8oC, it is stable up to 3 years?

  • QUESTION: How long is it stable if shipped at room temperature?
    ANSWER: We can ensure stability ≤ 72 hours without significant degradation or oxidation.
  • QUESTION: Does material need to be packaged under inert gas?
    ANSWER: Yes, argon preferred nitrogen also suitable.
  • QUESTION: Does DTT show degradation when stressed at 30oC?
    ANSWER: Yes, DTT demonstrates degradation starting after 3 days and increasing rapidly after 5 days.
  • QUESTION: What are the basic chemical data:
    ANSWER: Chemical Formula: C4H10O2S2, CAS Number:3483-12-3; EC Number (EINECS): 222-468-7.
  • QUESTION: What is the redox potential?
    ANSWER:-0.33 V at pH 7.
  • QUESTION: Is the reducing power limited?
    ANSWER: Yes, the reducing power is limited to pH values >7.
  • QUESTION: Can you identify some of the applications for DTT?
    ANSWER: 1.) A common use of DTT is as a reducing or "deprotecting" agent for thiolated DNA.2.) DTT is frequently used to reduce the disulfide bonds of proteins.

QUESTION: what is the current Merck Index #?
ANSWER: Merck 14th edition 14, 3376

  • QUESTION: Can you list key publications?
    ANSWER: References: 1. Biochemistry 3, 480 (1964) (see attached); 2. J. Biol. Chem. 243, 716 (1968); 3 Biochemical Education 11, 70 (1983).
  • QUESTION: What is DTT’s solubility?
    ANSWER: It is a clear, colorless solution at 50mg/ml in water. It is also freely soluble in ethanol, acetone, ethylate, chloroform and ether.
  • QUESTION: Additional solubility information:
    ANSWER: DTT is not stable in solution. Only freshly-made DTT solutions should be used. To prepare a 1 M DTT solution, dissolve 1.55 g of DTT powder in 10 ml of deionized (DI) water.
  • QUESTION: Is DTT stable?
    ANSWER: DTT is hygroscopic and has sensitivity to heat. Incompatible with strong oxidizing agents, and decomposes at pH >7.
  • QUESTION: What is DTT Melting Point?
    ANSWER: 42-43oC.
  • QUESTION: Is there a more stable reducing agent, especially in lower pH environment?
    ANSWER: Yes, TCEP, Tris(2-carboxyethyl)phosphine HCl, Product #T-1180.
  • QUESTION: Is a Molecular Biology grade DTT available?

ANSWER: Yes, Dithiothreitol, Molecular Biology Grade, It is tested to befree of the following: Protease, Rnase, Dnase, ICP metals. Inquire for current price & availability.

  • QUESTION: Too many bands on a Western Blot, Potential cause of DTT?
    ANSWER: h) Aggregation of analyte. Increase amount of DTT to ensure complete reducing of disulfide bonds (20 -100mM DTT). Heat in boiling water bath 5-10 minutes before loading onto gel. Perform a brief centrifugation.
  • QUESTION: Who was W. Wallace Cleland?
    ANSWER: Often credited with discovering DTT, aka Cleland’s Reagent. BRIEFBIO FOLLOWS: William Wallace Cleland was born in 1930 in Baltimore, Maryland. He received his A.B. from Oberlin College in 1950 and his M.S. and Ph.D. from the University of Wisconsin-Madison in 1953 and 1955, respectively. Cleland then did a postdoctoral fellowship at the University of Chicago, after which he returned to Madison to join the faculty of the University of Wisconsin as an Assistant Professor in 1959. He was promoted to Associate Professor in 1962, Professor in 1966, J. Johnson Professor of Biochemistry in 1978, and Steenbock Professor of Chemical Science in 1982. Cleland remains at the University of Wisconsin where he is still actively involved in research. When Cleland first joined the faculty at the University of Wisconsin, his main focus was lipids. He spent several years studying the substrate specificity for acyl-CoA thioesters in the acylation of glycerophosphate to phosphatidic acids.
  • QUESTION: Can DTT interfere with HIS-Tagged Proteins?
    ANSWER: YES, DTT reduces nickel ions and can cause problems when purifying His-tagged proteins.
  • QUESTION: Can DTT lead to non-specific aggregation?
    ANSWER: Yes, reducing agents like DTT are typically used to prevent the oxidation of free sulfhydryl residues (cysteines) in the protein. Such oxidation can lead to non-specific aggregation of the sample, sample heterogeneity, inactivity, or denaturation of the sample.
  • QUESTION: What special consideration should be followed with peptides containing cysteines.
    ANSWER: Peptides containing cysteine are prone to oxidative formation of disulfide bonds, which can form intramolecularly, forming a cyclic peptide, or intermolecularly, resulting in oligomerization. If more than one cysteine is present in a molecule, intramolecular disulfides will cause aggregation of the peptide molecules. Disulfide bonds can be reduced using DTT. However, some aggregates are very difficult to reduce. Since oxidation occurs most frequently after exposure of the deprotected peptide to air, care should be taken to keep the peptide as anaerobic as possible when multiple cysteines are present.
  • QUESTION: Do you have a quick recipe for DTT stock solution?
    ANSWER:ANSWER: Dithiothreitol reduces sulfides to their corresponding thiols. Dithiothreitol is soluble in water and alcohols and has a lower volatility than that of other reducing agents such as b-mercaptoethanol. At low concentrations DTT can be used in a reaction buffer to maintain enzymatic activities. In higher concentrations DTT dissociates disulfide linkages in polypeptides, which facilitates the denaturation by detergents or chaotropic agents.DirectionsDissolve DTT in 20 ml distilled H2O: 1 Molar 3.09 g, 0.1 Molar 0.309 g Sterilize by filtration (do not autoclave). Dispense into aliquots in microcentrifuge tubes.Store at -20°C.
  • QUESTION: is DTT, Dithiothreitol HAZARDOUS?
    ANSWER: Dithiothreitol is a highly toxic substance. Harmful if inhaled orswallowed. Avoid contact with eyes, skin, and clothing. Use only in a well- ventilated area. Wash thoroughly after handling.
    SEE MSDS that follows for full protection that must be followed prior to handling.