2-Mercaptoethanol
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| Names | |
|---|---|
| IUPAC name
2-Hydroxy-1-ethanethiol
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| Other names
2-Mercaptoethanol
Thioglycol β-Mercaptoethanol | |
| Identifiers | |
3D model (JSmol)
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| ECHA InfoCard | 100.000.422 |
CompTox Dashboard (EPA)
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| Properties | |
| 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)
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1.4996 |
| Related compounds | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2-Mercaptoethanol (also β-mercaptoethanol, or "2BME") 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.
Preparation
ME may be prepared by the action of hydrogen sulfide on ethylene oxide:[1]
Applications
Some proteins can be denatured by 2-mercaptoethanol via its ability to cleave disulfide bonds:
By breaking the S-S bonds, both the tertiary structure and the quaternary structure of some proteins can be disrupted.[2] Because of its ability to disrupt the structure of proteins, it is used in the analysis of proteins, for instance, to ensure that a protein solution contains monomeric protein molecules, instead of disulfide linked dimers or higher order oligomers.
2-Mercaptoethanol is often used interchangeably with dithiothreitol (DTT) or the odorless tris(2-carboxyethyl)phosphine (TCEP) in biological applications.
Reactions
2-Mercaptoethanol reacts with aldehydes and ketones to give the corresponding oxathiolanes. This makes 2-mercaptoethanol useful as a protecting group.[3]
Safety
2-Mercaptoethanol is considered a "severe" poison, causing irritation to the nasal passageways and respiratory tract upon inhalation, vomiting and stomach pain through ingestion, and potentially fatal absorption if it contacts the skin.[4]
Applications
Denaturing Ribonucleases
2-Mercaptoethanol is used in some RNA isolation procedures to eliminate ribonuclease released during cell lysis. Numerous [disulfide bonds] make ribonucleases very stable enzymes, so 2-mercaptoethanol is used to reduce these disulfide bonds and irreversibly denature the proteins. This prevent them from digesting the RNA during the procedure.[5]
References
- ^ 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-Mercaptoethanol". Chemicalland21.com.
- ^ "1,3-Dithiolanes, 1,3-Dithianes". Organic Chemistry Portal.
- ^ "Material Safety Data Sheet". ScienceLab.com.
- ^ Nelson, David R.; Lehninger, Albert L; Cox, Michael (2005). Lehninger principles of biochemistry. New York: W.H. Freeman. p. 148. ISBN 0-7167-4339-6.
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