2-Mercaptoethanol

From Wikipedia, the free encyclopedia

2-Mercaptoethanol
2-Mercaptoethanol
2-Mercaptoethanol
IUPAC name 2-Hydroxy-1-ethanethiol
Other names 2-Mercaptoethanol
Thioglycol
β-Mercaptoethanol
Identifiers
CAS number [60-24-2]
SMILES SCCO
Properties
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
Hazards
MSDS Oxford MSDS
EU classification Toxic (T)
R-phrases R23 R24 R25 R37 R38 R41
S-phrases S26 S36 S37 S39 S45 S53
Related compounds
Related compounds ethylene glycol
1,2-ethanedithiol
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 scavenging 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.

Contents

[edit] Preparation

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

Reaction scheme for the preparation of 2-mercaptoethanol from ethylene oxide and hydrogen sulfide

[edit] Applications

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

cysS-Scys + 2 HOCH2CH2SH → 2 cysSH + HOCH2CH2S-SCH2CH2OH
Reaction scheme for the cleavage of disulfide bonds by 2-mercaptoethanol

By breaking the S-S bonds, both the tertiary structure and the quaternary structure of the protein can be disrupted.[2] Because of its ability to disrupt the 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.

[edit] Reactions

2-Mercaptoethanol reacts with aldehydes and ketones to give the corresponding oxathiolanes. This makes 2-mercaptoethanol useful as a protecting group.[3]

Reaction scheme for the formation of oxathiolanes by reaction of 2-mercaptoethanol with aldehydes or ketones

[edit] Biological effects

2-Mercaptoethanol is one of the few chemicals that extends the maximum as well as the median life span of mice.[4] In microgram quantities, 2-mercaptoethanol has been observed to have a number of possibly beneficial effects on laboratory mice.[5]

[edit] References

  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. ^ 2-Mercaptoethanol. Chemicalland21.com.
  3. ^ 1,3-Dithiolanes, 1,3-Dithianes. Organic Chemistry Portal.
  4. ^ M.L. Heidrick, L.C. Hendricks and D.E. Cook (1984). "Effect of dietary 2-mercaptoethanol on the life span, immune system, tumor incidence and lipid peroxidation damage in spleen lymphocytes of aging BC3F1 mice". Mech. Ageing Dev. 27 (3): 341-58. doi:10.1016/0047-6374(84)90057-5. PMID 6334792. 
  5. ^ L. Pénzesa, R. C. Nobleb, E. Beregia, S. Imrec, J. Izsáka and O. Regius (1988). "Effect of 2-mercaptoethanol on some metabolic indices of ageing of CBA/Ca inbred mice". Mech. Ageing Dev. 45 (1): 75-92. doi:10.1016/0047-6374(88)90021-8. PMID 3216730.