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IUPAC name 2-Hydroxy-1-ethanethiol
Other names 2-Mercaptoethanol
CAS number 60-24-2
Molecular formula C2H6OS
Molar mass 78.13 g mol−1
Density 1.11 g cm−3
Melting point

−100 °C

Boiling point

157-158 °C

Refractive index (nD) 1.4996
Related Compounds
Related compounds ethylene glycol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

2-Mercaptoethanol (also β-mercaptoethanol) is the chemical compound with the formula HOCH2CH2SH. It is a hybrid of ethylene glycol, HOCH2CH2OH, and 1,2-ethanedithiol, HSCH2CH2SH. ME or βME, as it is commonly abbreviated, is used to reduce disulfide bonds and can act as a biological antioxidant by scavaging hydroxyl radicals (amongst others) . It is widely used because the hydroxyl group confers solubility in water and lowers the volatility. Due to its diminished vapor pressure, its odour, while unpleasant, is less objectionable than related thiols.

ME is prepared by the action of hydrogen sulfide on ethylene oxide:[1]


Biochemical properties

Proteins are denatured by 2-mercaptoethanol via its ability to cleave disulfide bonds:

cysS-Scys + 2 HOCH2CH2SH → 2 cysSH + HOCH2CH2S-SCH2CH2OH

By breaking the S-S bonds, the quaternary structure of the protein is disrupted.[2] Because of its ability to disrupt the quaternary structure of proteins, it is used in the analysis of proteins.

2-Mercaptoethanol is often used interchangeably with dithiothreitol (DTT) or the odorless tris(2-carboxyethyl)phosphine (TCEP) in biological applications.

Biomedical consequences

2-Mercaptoethanol is one of the few chemicals that extends the maximum as well as the median life span of mice.[3] In microgram quantities, 2-mercaptoethanol has been observed to have a number of possibly beneficial effects on laboratory mice.[4]

Organic chemistry

ME reacts with aldehydes and ketones to give the corresponding oxathiolanes:


  1. ^ Knight, J. J. "2-Mercaptoethanol" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
  2. ^ Chemicalland: 2-mercaptoethanol
  3. ^ Yu, B.P.; Kang, C.M., Han, J.S., Kim, D.S. "Can antioxidant supplementation slow the aging process?" Biofactors 1998, Volume 7: pages93-101. "Can antioxidant supplementation slow the aging process?
  4. ^ Effect of 2-mercaptoethanol on some metabolic indices of ageing of CBA/Ca inbred mice
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "2-Mercaptoethanol". A list of authors is available in Wikipedia.
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