2-mercaptoethanol 2-mercaptoethanol 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). 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 related thiols. 2-mercaptoethanol names preferred iupac name 2-sulfanylethan-1-ol other names 2-mercaptoethan-1-ol2-hydroxy-1-ethanethiolβ-mercaptoethanolthioglycolbeta-merc identifiers cas number 60-24-2 y 3d model (jsmol) interactive image 3dmet b00201 beilstein reference 773648 chebi chebi:41218 y chembl chembl254951 y chemspider 1512 y drugbank db03345 y echa infocard 100.000.422 ec number 200-464-6 gmelin reference 1368 kegg c00928 n mesh mercaptoethanol pubchem cid 1567 rtecs number kl5600000 unii 14r9k67urn y un number 2966 comptox dashboard (epa) dtxsid4026343 inchi inchi=1s/c2h6os/c3-1-2-4/h3-4h,1-2h2 ykey: dgvvwutypxicam-uhfffaoysa-n y smiles occs properties 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 hazards ghs labelling: pictograms signal word danger hazard statements h301, h310, h315, h317, h318, h330, h410 precautionary statements 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)150 mg/kg (skin, rabbit) related compounds related compounds ethylene glycol1,2-ethanedithiol except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). n verify (what is yn ?) infobox references production 2-mercaptoethanol is manufactured industrially by the reaction of ethylene oxide with hydrogen sulfide. thiodiglycol and various zeolites catalyze the reaction. reactions 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. applications 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: rs–sr + 2 hoch2ch2sh ⇌ 2 rsh + hoch2ch2s–sch2ch2oh 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. it 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. safety 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.