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.
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.[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 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.[7]
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.[8][9]
Preventing protein oxidationedit
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]
Denaturing ribonucleasesedit
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.[11]
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]
^Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 697. doi:10.1039/9781849733069-FP001. ISBN978-0-85404-182-4. The prefixes 'mercapto' (–SH), and 'hydroseleno' or selenyl (–SeH), etc. are no longer recommended.
^"1,3-Dithiolanes, 1,3-Dithianes". Organic Chemistry Portal. from the original on 17 May 2008. Retrieved 27 May 2008.
^Sartori, Giovanni; Ballini, Roberto; Bigi, Franca; Bosica, Giovanna; Maggi, Raimondo; Righi, Paolo (2004). "Protection (and Deprotection) of Functional Groups in Organic Synthesis by Heterogeneous Catalysis". Chem. Rev. 104 (1): 199–250. doi:10.1021/cr0200769. PMID 14719975.
^. Chemicalland21.com. Archived from the original on 2006-10-05. Retrieved 8 October 2006.
^Aitken CE; Marshall RA, Puglisi JD (2008). "An oxygen scavenging system for improvement of dye stability in single-molecule fluorescence experiments". Biophys J. 94 (5): 1826–35. Bibcode:2008BpJ....94.1826A. doi:10.1529/biophysj.107.117689. PMC2242739. PMID 17921203.
^Yeh, J. I. (2009) "Additives and microcalorimetric approaches for optimization of crystallization" in Protein Crystallization, 2nd Edition (Ed: T. Bergfors), International University Line, La Jolla, CA. ISBN978-0-9720774-4-6.
^Stevens R.; Stevens L.; Price N.C. (1983). "The Stabilities of Various Thiol Compounds used in Protein Purifications". Biochemical Education. 11 (2): 70. doi:10.1016/0307-4412(83)90048-1.
^Verduyn, C; Van Kleef, R; Frank, J; Schreuder, H; Van Dijken, J. P.; Scheffers, W. A. (1985). "Properties of the NAD(P)H-dependent xylose reductase from the xylose-fermenting yeast Pichia stipitis". The Biochemical Journal. 226 (3): 669–77. doi:10.1042/bj2260669. PMC1144764. PMID 3921014.
^Nelson, David R.; Lehninger, Albert L; Cox, Michael (2005). Lehninger principles of biochemistry. New York: W.H. Freeman. pp. 148. ISBN0-7167-4339-6.
^Scattolin, Thomas; Gharbaoui, Tawfik; Chen, Cheng-yi (2022). "A Nucleophilic Deprotection of Carbamate Mediated by 2-Mercaptoethanol". Organic Letters. 24 (20): 3736–3740. doi:10.1021/acs.orglett.2c01410. PMID 35559611. S2CID 248776636.
^"Material Safety Data Sheet". Merck. Retrieved 24 September 2023.
April 12, 2024
mercaptoethanol, also, mercaptoethanol, 2bme, chemical, compound, with, formula, hoch2ch2sh, βme, commonly, abbreviated, used, reduce, disulfide, bonds, biological, antioxidant, scavenging, hydroxyl, radicals, amongst, others, widely, used, because, hydroxyl, . 2 Mercaptoethanol also b mercaptoethanol BME 2BME 2 ME or b met is the chemical compound with the formula HOCH2CH2SH ME or bME 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 NamesPreferred IUPAC name 2 Sulfanylethan 1 ol 1 Other names 2 Mercaptoethan 1 ol2 Hydroxy 1 ethanethiolb MercaptoethanolThioglycolBeta mercIdentifiersCAS Number 60 24 2 Y3D model JSmol Interactive image3DMet B00201Beilstein Reference 773648ChEBI CHEBI 41218 YChEMBL ChEMBL254951 YChemSpider 1512 YDrugBank DB03345 YECHA InfoCard 100 000 422EC Number 200 464 6Gmelin Reference 1368KEGG C00928 NMeSH MercaptoethanolPubChem CID 1567RTECS number KL5600000UNII 14R9K67URN YUN number 2966CompTox Dashboard EPA DTXSID4026343InChI InChI 1S C2H6OS c3 1 2 4 h3 4H 1 2H2 YKey DGVVWUTYPXICAM UHFFFAOYSA N YSMILES OCCSPropertiesChemical formula C 2H 6O SMolar mass 78 13 g mol 1Odor Disagreeable distinctiveDensity 1 114 g cm3Melting point 100 C 148 F 173 K Boiling point 157 C 314 F 430 Klog P 0 23Vapor pressure 0 76 hPa at 20 C 4 67 hPa at 40 C Acidity pKa 9 643Basicity pKb 4 354Refractive index nD 1 4996HazardsGHS labelling PictogramsSignal word DangerHazard statements H301 H310 H315 H317 H318 H330 H410Precautionary statements P260 P273 P280 P284 P301 P310 P302 P350Flash 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 compoundsRelated compounds Ethylene glycol1 2 EthanedithiolExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Contents 1 Production 2 Reactions 3 Applications 3 1 Reducing proteins 3 2 Preventing protein oxidation 3 3 Denaturing ribonucleases 3 4 Deprotecting carbamates 4 Safety 5 See also 6 ReferencesProduction edit2 Mercaptoethanol is manufactured industrially by the reaction of ethylene oxide with hydrogen sulfide Thiodiglycol and various zeolites catalyze the reaction 3 nbsp Reactions edit2 Mercaptoethanol reacts with aldehydes and ketones to give the corresponding oxathiolanes 4 This makes 2 mercaptoethanol useful as a protecting group giving a derivative whose stability is between that of a dioxolane and a dithiolane 5 nbsp Applications editReducing proteins edit 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 nbsp By breaking the S S bonds both the tertiary structure and the quaternary 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 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 7 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 8 9 Preventing protein oxidation edit 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 Denaturing ribonucleases edit 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 11 Deprotecting carbamates edit 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 12 Safety edit2 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 See also editDithiothreitol DTT Dithiobutylamine DTBA TCEPReferences edit Nomenclature of Organic Chemistry IUPAC Recommendations and Preferred Names 2013 Blue Book Cambridge The Royal Society of Chemistry 2014 p 697 doi 10 1039 9781849733069 FP001 ISBN 978 0 85404 182 4 The prefixes mercapto SH and hydroseleno or selenyl SeH etc are no longer recommended a b 2 Mercaptoethanol Roy Kathrin Maria 2005 Thiols and Organic sulphides Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a26 767 ISBN 978 3527306732 1 3 Dithiolanes 1 3 Dithianes Organic Chemistry Portal Archived from the original on 17 May 2008 Retrieved 27 May 2008 Sartori Giovanni Ballini Roberto Bigi Franca Bosica Giovanna Maggi Raimondo Righi Paolo 2004 Protection and Deprotection of Functional Groups in Organic Synthesis by Heterogeneous Catalysis Chem Rev 104 1 199 250 doi 10 1021 cr0200769 PMID 14719975 2 Mercaptoethanol Chemicalland21 com Archived from the original on 2006 10 05 Retrieved 8 October 2006 Aitken CE Marshall RA Puglisi JD 2008 An oxygen scavenging system for improvement of dye stability in single molecule fluorescence experiments Biophys J 94 5 1826 35 Bibcode 2008BpJ 94 1826A doi 10 1529 biophysj 107 117689 PMC 2242739 PMID 17921203 Yeh J I 2009 Additives and microcalorimetric approaches for optimization of crystallization in Protein Crystallization 2nd Edition Ed T Bergfors International University Line La Jolla CA ISBN 978 0 9720774 4 6 Stevens R Stevens L Price N C 1983 The Stabilities of Various Thiol Compounds used in Protein Purifications Biochemical Education 11 2 70 doi 10 1016 0307 4412 83 90048 1 Verduyn C Van Kleef R Frank J Schreuder H Van Dijken J P Scheffers W A 1985 Properties of the NAD P H dependent xylose reductase from the xylose fermenting yeast Pichia stipitis The Biochemical Journal 226 3 669 77 doi 10 1042 bj2260669 PMC 1144764 PMID 3921014 Nelson David R Lehninger Albert L Cox Michael 2005 Lehninger principles of biochemistry New York W H Freeman pp 148 ISBN 0 7167 4339 6 Scattolin Thomas Gharbaoui Tawfik Chen Cheng yi 2022 A Nucleophilic Deprotection of Carbamate Mediated by 2 Mercaptoethanol Organic Letters 24 20 3736 3740 doi 10 1021 acs orglett 2c01410 PMID 35559611 S2CID 248776636 Material Safety Data Sheet Merck Retrieved 24 September 2023 Retrieved from https en wikipedia org w index php title 2 Mercaptoethanol amp oldid 1195472662, wikipedia, wiki, book, books, library,
