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| Names | |
|---|---|
| Preferred IUPAC name 2-Sulfanylethan-1-ol[1] | |
| Other names 2-Mercaptoethan-1-ol 2-Hydroxy-1-ethanethiol β-Mercaptoethanol Thioglycol Beta-merc | |
| Identifiers | |
| |
3D model (JSmol) | |
| 773648 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| DrugBank |
|
| ECHA InfoCard | 100.000.422 |
| EC Number |
|
| 1368 | |
| KEGG |
|
| MeSH | Mercaptoethanol |
| RTECS number |
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| UNII | |
| UN number | 2966 |
| |
| |
| Properties | |
| C2H6OS | |
| Molar mass | 78.13 g·mol−1 |
| Odor | Disagreeable, distinctive |
| Density | 1.114 g/cm3 |
| Melting point | −100 °C (−148 °F; 173 K) |
| Boiling point | 157 °C; 314 °F; 430 K |
| logP | −0.23 |
| Vapor pressure | 0.76 hPa (at 20 °C); 4.67 hPa (at 40 °C) |
| Acidity (pKa) | 9.643 |
| Basicity (pKb) | 4.354 |
Refractive index (nD) | 1.4996 |
| Hazards | |
| GHS labelling: | |
   | |
| Danger | |
| H301,H310,H315,H317,H318,H330,H410 | |
| P260,P273,P280,P284,P301+P310,P302+P350 | |
| Flash point | 68 °C (154 °F; 341 K) |
| Explosive limits | 18% |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 244 mg/kg (oral, rat)[2] 150 mg/kg (skin, rabbit)[2] |
| Related compounds | |
Related compounds | Ethylene glycol 1,2-Ethanedithiol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
2-Mercaptoethanol (alsoβ-mercaptoethanol,BME,2BME,2-ME orβ-met) is thechemical compound with theformula HOCH2CH2SH. ME or βME, as it is commonly abbreviated, is used to reducedisulfide bonds and can act as a biologicalantioxidant 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 odor, while unpleasant, is less objectionable than relatedthiols.
2-Mercaptoethanol is manufactured industrially by the reaction ofethylene oxide withhydrogen sulfide.Thiodiglycol and various zeolites catalyze the reaction.[3]
2-Mercaptoethanol reacts withaldehydes andketones to give the correspondingoxathiolanes.[4] This makes 2-mercaptoethanol useful as aprotecting group, giving a derivative whose stability is between that of adioxolane and adithiolane.[5]
Some proteins can be denatured by 2-mercaptoethanol, which cleaves thedisulfide bonds that may form betweenthiol groups ofcysteine residues. In the case of excess 2-mercaptoethanol, the following equilibrium is shifted to the right:
By breaking the S-S bonds, both thetertiary structure and thequaternary structure of some proteins can be disrupted.[6] Because of its ability to disrupt the structure of proteins, it was used in the analysis of proteins, for instance, to ensure that a protein solution contains monomeric protein molecules, instead of disulfide linkeddimers or higher orderoligomers. However, since 2-mercaptoethanol forms adducts with free cysteines and is somewhat more toxic,dithiothreitol (DTT) is generally more used especially inSDS-PAGE. DTT is also a more powerful reducing agent with aredox potential (at pH 7) of −0.33 V, compared to −0.26 V for 2-mercaptoethanol.[7]
2-Mercaptoethanol is often used interchangeably withdithiothreitol (DTT) or the odorlesstris(2-carboxyethyl)phosphine (TCEP) in biological applications.
Although 2-mercaptoethanol has a higher volatility than DTT, it is more stable: 2-mercaptoethanol'shalf-life is more than 100 hours atpH 6.5 and 4 hours at pH 8.5; DTT's half-life is 40 hours at pH 6.5 and 1.5 hours at pH 8.5.[8][9]
2-Mercaptoethanol and related reducing agents (e.g., DTT) are often included in enzymatic reactions to inhibit the oxidation of free sulfhydryl residues, and hence maintain protein activity. It is often used in enzyme assays as a standard buffer component.[10]
2-Mercaptoethanol is used in some RNA isolation procedures to eliminateribonuclease released during cell lysis. Numerousdisulfide bonds make ribonucleases very stable enzymes, so 2-mercaptoethanol is used to reduce these disulfide bonds and irreversibly denature the proteins. This prevents them from digesting the RNA during its extraction procedure.[11]
Somecarbamate protecting groups such ascarboxybenzyl (Cbz) or allyloxycarbonyl (alloc) can be deprotected using 2-mercaptoethanol in the presence ofpotassium phosphate indimethylacetamide.[12]
2-Mercaptoethanol is considered toxic, causing irritation to the nasal passageways and respiratory tract upon inhalation, irritation to the skin, vomiting and stomach pain through ingestion, and potentially death if severe exposure occurs.[13]
The prefixes 'mercapto' (–SH), and 'hydroseleno' or selenyl (–SeH), etc. are no longer recommended.
| Authority control databases: National |
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