- Formula: C3H7NO2S
- Molecular weight: 121.158
- IUPAC Standard InChI:
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- IUPAC Standard InChIKey: XUJNEKJLAYXESH-UWTATZPHSA-N
- CAS Registry Number: 52-90-4
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
- Other names: Cysteine, L-; «beta»-Mercaptoalanine; Cystein; Cysteine; Half-cystine; L-(+)-Cysteine; L-Alanine, 3-mercapto-; NSC-8746; Propanoic Acid, 2-amino-3-mercapto-, (R)-; Thioserine; (R)-2-Amino-3-mercaptopropanoic acid; «alpha»-Amino-«beta»-thiolpropionic acid; (R)-Cysteine; 2-Amino-3-mercaptopropionic acid; L-Cys
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Gas phase ion energetics data
Go To: Top, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
Data compiled as indicated in comments:
B - John E. Bartmess
|Proton affinity (review)||903.2||kJ/mol||N/A||Hunter and Lias, 1998||HL|
|Gas basicity||869.3||kJ/mol||N/A||Hunter and Lias, 1998||HL|
C3H6NO2S- + =
By formula: C3H6NO2S- + H+ = C3H7NO2S
|rH°||1395. ± 9.2||kJ/mol||CIDC||Jones, Bernier, et al., 2007||gas phase; B|
|rH°||1399. ± 9.6||kJ/mol||G+TS||Tian, Pawlow, et al., 2007||gas phase; Calcn say SH is 3.1 kcal/mol more acidic than CO2H. See DeBlase, Kass, et al., 2014 for spectroscopy saying that it is a cyclic H-bonded species; B|
|rG°||1370. ± 8.8||kJ/mol||N/A||Tian, Pawlow, et al., 2007||gas phase; Calcn say SH is 3.1 kcal/mol more acidic than CO2H. See DeBlase, Kass, et al., 2014 for spectroscopy saying that it is a cyclic H-bonded species; B|
|rG°||1364. ± 13.||kJ/mol||CIDC||O'Hair, Bowie, et al., 1992||gas phase; B|
Go To: Top, Gas phase ion energetics data, Notes
Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]
Jones, Bernier, et al., 2007
Jones, C.M.; Bernier, M.; Carson, E.; Colyer, K.E.; Metz, R.; Pawlow, A.; Wischow, E.D.; Webb, I.; Andriole, E.J.; Poutsma, J.C., Gas-phase Acities of the 20 Protein Amino Acids, Int. J. Mass Spectrom., 2007, 267, 1-3, 54-62, https://doi.org/10.1016/j.ijms.2007.02.018 . [all data]
Tian, Pawlow, et al., 2007
Tian, Z.X.; Pawlow, A.; Poutsma, J.C.; Kass, S.R., Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidity, H/D exchange experiments, and computations on cysteine and its conjugate base, J. Am. Chem. Soc., 2007, 129, 17, 5403-5407, https://doi.org/10.1021/ja0666194 . [all data]
DeBlase, Kass, et al., 2014
DeBlase, A.F.; Kass, S.R.; Johnson, M.A., On the character of the cyclic ionic H-bond in cryogenically cooled deprotonated cysteine, Phys. Chem. Chem. Phys., 2014, 16, 10, 4569-4575, https://doi.org/10.1039/c3cp54117g . [all data]
O'Hair, Bowie, et al., 1992
O'Hair, R.J.; Bowie, J.H.; Gronert, S., Gas Phase Acidity of the alpha-Amino Acids, Int. J. Mass Spectrom. Ion Proc., 1992, 117, 23, https://doi.org/10.1016/0168-1176(92)80083-D . [all data]
Go To: Top, Gas phase ion energetics data, References
- Symbols used in this document:
rG° Free energy of reaction at standard conditions rH° Enthalpy of reaction at standard conditions
- Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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