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CAS: 60-24-2
EC Number: 200-464-6
Chemical formula: HSCH₂CH₂OH
Molar Mass: 78.13 g/mol
IUPAC Name: 2-sulfanylethanol

2-mercaptoethanol is a thiol compound, commonly used as a reducing agent in organic reactions.
2-Mercaptoethanol (also β-mercaptoethanol, BME, 2BME, 2-ME or β-met) is the chemical compound with the formula HOCH2CH2SH. 
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). . 
Due to its diminished vapor pressure, its odor, while unpleasant, is less objectionable than related thiols.
2-Mercaptoethanol (also known as beta-mercaptoethanol or BME) is a potent reducing agent used in cell culture media to prevent toxic levels of oxygen radicals. 
2-Mercaptoethanol is not stable in solution, so most protocols require daily supplementation. 
Thioglycol appears as a water-white liquid. 
2-Mercaptoethanol May be toxic by ingestion, inhalation, or skin absorption.
Mercaptoethanol is a primary alcohol and an alkanethiol. 
2-Mercaptoethanol has a role as a geroprotector.
2-Mercaptoethanol is a water-soluble thiol derived from hydrogen sulfide and ethanol. 
2-Mercaptoethanol is used as a reducing agent for disulfide bonds and to protect sulfhydryl groups from oxidation.

2-Mercaptoethanol is used to reduce disulfide linkages in solubilizing proteins for gel electrophoresis (typically used in SDS-PAGE sample buffer at 5% concentration). 
Also it reduces excess oxidative polymerization of catalysts. 
Cleaving intermolecular (between subunits) disulfide bonds allows the subunits of a protein to separate independently on SDS-PAGE. 
Cleaving intramolecular (within subunit) disulfide bonds allows the subunits to become completely denatured so that each peptide migrates according to its chain length with no influence due to secondary structure.
In solution, 2-mercaptoethanol is readily oxidized in air to a disulfide, especially at alkaline pH. Because of this property, 2-Mercaptoethanol is widely used to protect proteins, enzymes in particular, from becoming inactive. 
An excess of 2-mercaptoethanol (generally used at 0.01 M) will maintain the protein thiol groups in their reduced state.

The addition of a reducing agent to an assay may be important to prevent the oxidation of cysteines in the proteins being studied and thus the formation of disulfides. 
The most commonly used reducing agents are dithiothreitol (DTT), β-mercaptoethanol (β-ME) and tris(2-carboxyethyl)phosphine (TCEP).
2-mercaptoethanol or β-mercaptoethanol or BME is a chemical compound of the formula HOCH2CH2SH, a "hybrid" of ethylene glycol and ethanedithiol. 
At room temperature it is a liquid with a foul-smelling odor. 
The presence of the thiol -SH function makes 2-mercaptoethanol a reducing agent widely used in biochemistry to protect proteins against oxidation.
The denaturation of proteins requires the reduction of disulfide bridges, which are crucial for the tertiary or quaternary structure of certain proteins. 
β-Mercaptoethanol can act as an enzyme reactivator in systems necessitating reduction for activation, and has been commonly used to reduce disulfide bonds in order to separate protein subunits for use in electrophoresis. 
This product can also be used to form o-Phthalaldehyde-beta-mercaptoethanol (OPAME), a fluorogenic reagent shown to detect amino acids based on its reaction with primary amines. 
More recently OPAME has been used to distinguish between ssDNA/dsDNA and even single base mismatches in the hybridization of DNA.

Mercaptoethanol, also called beta-mercaptoethanol, BME, or 2-Mercaptoethanol, is a potent reducing agent that effectively cleaves and reduces disulfide bonds. 
2-Mercaptoethanol disrupts tertiary and quaternary protein structures and is often used to unfold native proteins. 
This property makes mercaptoethanol a useful reagent for preparing samples in denaturing protein electrophoresis, as well as for inactivating ribonucleases during some RNA isolation procedures. 
2-Mercaptoethanol has also been used in mammalian cell culture media to prevent toxic levels of oxygen radicals. 
Mercaptoethanol is an alternative to dithiothreitol (DTT), but DTT is more popular for use in SDS-PAGE as it is less toxic and less reactive. 
Mercaptoethanol is not stable in solution, so most protocols require daily supplementation. 

CAS: 60-24-2
EC Number: 200-464-6
Chemical formula: HSCH₂CH₂OH
Molar Mass: 78.13 g/mol
IUPAC Name: 2-sulfanylethanol

2-Mercaptoethanol is manufactured industrially by the reaction of ethylene oxide with hydrogen sulfide. 
Thiodiglycol and various zeolites catalyze the reaction.
Reaction of ethylene oxide with hydrogen sulfide to form 2-mercaptoethanol in the presence of thiodiglycol as solvent and catalyst.
2-Mercaptoethanol reacts with aldehydes and ketones to give the corresponding oxathiolanes.
This makes 2-mercaptoethanol useful as a protecting group, giving a derivative whose stability is between that of a dioxolane and a dithiolane.
Reaction scheme for the formation of oxathiolanes by reaction of 2-mercaptoethanol with aldehydes or ketones.


Reducing proteins:
Some proteins can be denatured by 2-mercaptoethanol, which cleaves the disulfide bonds that may form between thiol groups of cysteine residues. 
In the case of excess 2-mercaptoethanol, the following equilibrium is shifted to the right:
By breaking the S-S bonds, both the tertiary structure and the quaternary structure of some proteins can be disrupted. 
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 linked dimers or higher order oligomers. 
However, since 2-mercaptoethanol forms adducts with free cysteines and is somewhat more toxic, dithiothreitol (DTT) is generally more used especially in SDS-PAGE. 
DTT is also a more powerful reducing agent with a redox potential (at pH 7) of −0.33 V, compared to −0.26 V for 2-mercaptoethanol.
2-Mercaptoethanol is often used interchangeably with dithiothreitol (DTT) or the odorless tris(2-carboxyethyl)phosphine (TCEP) in biological applications.
Although 2-mercaptoethanol has a higher volatility than DTT, it is more stable: 2-mercaptoethanol's half-life is more than 100 hours at pH 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.
Preventing protein oxidation:
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. 
2-Mercaptoethanol is often used in enzyme assays as a standard buffer component.

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 prevents them from digesting the RNA during its extraction procedure.

Deprotecting carbamates:
Some carbamate protecting groups such as carboxybenzyl (Cbz) or allyloxycarbonyl (alloc) can be deprotected using 2-mercaptoethanol in the presence of potassium phosphate in dimethylacetamide.

2-mercaptoethanol is commonly used to reduce disulfide bridges present in proteins and can play a role as a biological antioxidant. 
2-mercaptoethanol is also used because of its hydroxyl group, which makes it miscible in water and reduces the volatility (and therefore the odor) of thiol.
2-Mercaptoethanol is a powerful reducing agent used in cell culture media to prevent toxic levels of oxygen radicals.
2-mercaptoethanol is widely used because the hydroxyl group confers solubility in water and lowers the volatility

Solubilizes proteins by reducing disulfide linkages 2-Mercaptoethanol is used in the preparation of nano-graphene for cellular imaging and drug delivery as well as multifunctional polymeric micelle. 
2-mercaptoethanol acts as a reducing agent used in electrophoresis, amino acid detection, and distinguishing ssDNA/dsDNA. 
2-mercaptoethanol is also employed as a standard buffer. 
2-mercaptoethanol is also used in the preparation of PVC heat stabilizers and as a chain transfer agent in the manufacture of PVC. 
Further, 2-mercaptoethanol is used in some RNA isolation procedures to eliminate ribonuclease. 
2-mercaptoethanol is utilized as a corrosion inhibitor and ore floatation agent. 
In biochemistry, 2-mercaptoethanol is useful to study the activity of the immune system.

CAS: 60-24-2
EC Number: 200-464-6
Chemical formula: HSCH₂CH₂OH
Molar Mass: 78.13 g/mol
IUPAC Name: 2-sulfanylethanol

Boiling point:    154 - 161 °C (1013 hPa)
Density    : 1.11 g/cm3 (20 °C)
Explosion limit:    2.3 - 18 %(V)
Flash point:    70.5 °C
Ignition temperature:    295 °C
Melting Point:    <-50 °C
pH value:    4.5 - 6 (500 g/l, H₂O, 20 °C)
Vapor pressure:    0.76 hPa (20 °C)
vapor density: 2.69 (vs air)
Quality Level: 200
vapor pressure: 1 mmHg ( 20 °C)
Form: liquid
expl. lim.: 18 %
Concentration: 14.3 M (pure liquid)
refractive index: n20/D 1.500 (lit.)
pH: 4.5-6 (20 °C, 500 g/L)
bp: 157 °C (lit.)
Chemical formula:    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
log P:    −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
Storage temp.:      2-8°C
Molecular Weight:    78.14    
XLogP3-AA:    -0.2    
Hydrogen Bond Donor Count:    2    
Hydrogen Bond Acceptor Count:    2    
Rotatable Bond Count:    1    
Exact Mass:    78.01393598    
Monoisotopic Mass:    78.01393598    
Topological Polar Surface Area:    21.2 Ų    
Heavy Atom Count:    4    
Formal Charge:    0    
Complexity:    10 
Isotope Atom Count:    0    
Defined Atom Stereocenter Count:    0    
Undefined Atom Stereocenter Count:    0    
Defined Bond Stereocenter Count:    0    
Undefined Bond Stereocenter Count:    0    
Covalently-Bonded Unit Count:    1    
Compound Is Canonicalized:    Yes
Color/Form: Water-white mobile liquid
Odor:  Strong disagreeable odor
Henry's Law constant = 1.3X10-7 atm-cu m/mol at 25 °C (est)
Autoignition Temperature: 295 °C
Decomposition: When heated to decomposition it emits highly toxic fumes of /sulfur oxides/.
Viscosity: 3.43 cP

CAS: 60-24-2
EC Number: 200-464-6
Chemical formula: HSCH₂CH₂OH
Molar Mass: 78.13 g/mol
IUPAC Name: 2-sulfanylethanol

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.

First Aid Measures:
Description of first aid measures
General advice:
Consult a physician. 
Show this safety data sheet to the doctor in attendance.
If inhaled:
If breathed in, move person into fresh air. 
If not breathing, give artificial respiration. 
Consult a physician.
In case of skin contact:
Wash with plenty of soap and water. 
Consult a physician.
In case of eye contact:
Rinse immediately with plenty of water for at least 15 minutes. 
Consult a physician.
If swallowed:
Do NOT induce vomiting. 
Never give anything by mouth to an unconscious person. 
Rinse mouth with water. 
Consult a physician.
 Most important symptoms and effects, both acute and delayed
The most important known symptoms and effects are described in the labeling 
Fire Fighting Measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Sulphur oxides
Precautions for fire-fighters
Wear self contained breathing apparatus for fire fighting if necessary
Accidental Release Measures:
Personal precautions, protective equipment and emergency procedures
Wear respiratory protection.
Avoid breathing vapours, mist or gas. 
Ensure adequate ventilation.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains. 
Discharge into environment must be avoided.
Methods and materials for containment and cleaning up
Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing
and place in container for disposal according to local regulations
Keep in suitable, closed containers for disposal.
Reference to other sections
Handling and Storage:
 Precautions for safe handling
Avoid contact with skin and eyes.
Avoid inhalation of dust and aerosols. 
Provide appropriate exhaust ventilation at places where dust is formed.
Keep away from sources of heat and ignition  smoking 
Conditions for safe storage, including any incompatibilities
Store in cool place. 
Keep container tightly closed in a dry and well-ventilated place.
Recommended Storage Temperature : Below 30°C
Exposure Controls/Personal Protection
Control parameters:
Components with workplace control parameters
Exposure controls:
Appropriate engineering controls
Handle in accordance to general industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Hygiene measure:
Immediately change contaminated clothing. 
Apply preventive skin protection. 
Wash hands and face after working with the product.
Eye/face protection:
Faceshield and safety goggles.
Skin protection:

Handle with gloves.
Body protection:
Complete suit protecting against chemicals.
Respiratory protection:
Air-purifying respirators.
Environment exposure controls
Prevent further leakage or spillage if safe to do so. 
Do not let product enter drains. 
Discharge into the environment must be avoided.
Disposal Considerations:
 Waste treatments methods
Burn in a chemical incinerator equipped with an after burner and scrubber but exert extra care in
igniting as this material is highly flammable.
Contaminated packaging
Dispose of as unused product

CAS: 60-24-2
EC Number: 200-464-6
Chemical formula: HSCH₂CH₂OH
Molar Mass: 78.13 g/mol
IUPAC Name: 2-sulfanylethanol


MeSH Entry Terms:
2 Mercaptoethanol




Depositor-Supplied Synonyms:






Ethanol, 2-mercapto-



Thioethylene glycol


2-Hydroxyethyl mercaptan





Hydroxyethyl mercaptan

Monothioethylene glycol

2-Mercaptoethyl alcohol


Ethylene glycol, monothio-




Emery 5791

USAF EK-4196




NSC 3723


2-mercapto ethanol








2-Mercaptoethanol, >=99.0%



Cuprate(6-), .mu.-2,2-(1-methyl-1,2-ethanediyl)bisimino(6-fluoro-1,3,5-triazine-4,2-diyl)imino(2-hyd

CCRIS 2097

HSDB 5199

EINECS 200-464-6


BRN 0773648







hydroxyethyl sulfide

mercaptoethyl alcohol


2-Sulfanylethanol #





EC 200-464-6

4-01-00-02428 (Beilstein Handbook Reference)









Thioglycol [UN2966] [Poison]



2-Mercaptoethanol, for electrophoresis





UN 2966



2-Mercaptoethanol, for synthesis, 99.0%





2-Mercaptoethanol, SAJ special grade, >=99.0%




3-Pyridinecarbonitrile, 4-methyl-2,6-di-5-morpholinyl-


2-Mercaptoethanol, for HPLC derivatization, >=99.0% (GC)

2-Mercaptoethanol, BioUltra, for molecular biology, >=99.0% (GC)

2-Mercaptoethanol, for molecular biology, for electrophoresis, suitable for cell culture, BioReagent, 99% (GC/titration)

2-Mercaptoethanol, PharmaGrade, Manufactured under appropriate controls for use as raw material in pharma or biopharmaceutical production.

Cuprate(6-), [.mu.-[[2,2'-[(1-methyl-1,2-ethanediyl)bis[imino(6-fluoro-1,3,5-triazine-4,2-diyl)imino[2-(hydroxy-.kappa.O)-5-sulfo-3,1-phenylene](2,1-diazenediyl-.kappa.N2)(phenylmethylene)-2,1-diazenediyl-.kappa.N1]]bis[4-sulfobenzoato-.kappa.O]](10-)]]di-, sodium

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