L-Cysteine
- Formula: C3H7NO2S
- Molecular weight: 121.158
- 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
The 3d structure may be viewed using Java or Javascript. - Stereoisomers:
- Other names: Cysteine, L-; β-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; α-Amino-β-thiolpropionic acid; (R)-Cysteine; 2-Amino-3-mercaptopropionic acid; L-Cys
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Condensed phase thermochemistry data
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, UV/Visible spectrum, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°solid | -534.08 ± 0.62 | kJ/mol | Ccr | Sabbah and Minadakis, 1981 | ALS |
ΔfH°solid | -567.4 | kJ/mol | Ccb | Becker and Roth, 1934 | hf_H2SO4.10,000H2O=-900.752 kJ/mol; ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°solid | -2248.84 ± 0.55 | kJ/mol | Ccr | Sabbah and Minadakis, 1981 | ALS |
ΔcH°solid | -2267.7 ± 2.1 | kJ/mol | Ccr | Sunner, 1946 | Reanalyzed by Cox and Pilcher, 1970, Original value = -2268.9 kJ/mol; ALS |
ΔcH°solid | -2248.9 ± 2.1 | kJ/mol | Ccb | Huffman and Ellis, 1935 | Reanalyzed by Cox and Pilcher, 1970, Original value = -2223.3 ± 2.1 kJ/mol; ALS |
ΔcH°solid | -2229. ± 3. | kJ/mol | Ccb | Becker and Roth, 1934 | hf_H2SO4.10,000H2O=-900.752 kJ/mol; ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°solid,1 bar | 169.9 | J/mol*K | N/A | Huffman and Ellis, 1935, 2 | Extrapolation below 90 K, 48.99 J/mol*K.; DH |
Constant pressure heat capacity of solid
Cp,solid (J/mol*K) | Temperature (K) | Reference | Comment |
---|---|---|---|
162.3 | 297.6 | Huffman and Ellis, 1935, 2 | T = 85 to 298 K. Value is unsmoothed experimental datum.; DH |
Reaction thermochemistry data
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: John E. Bartmess
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
C3H6NO2S- + =
By formula: C3H6NO2S- + H+ = C3H7NO2S
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1395. ± 9.2 | kJ/mol | CIDC | Jones, Bernier, et al., 2007 | gas phase |
ΔrH° | 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 |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 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 |
ΔrG° | 1364. ± 13. | kJ/mol | CIDC | O'Hair, Bowie, et al., 1992 | gas phase |
Gas phase ion energetics data
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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
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Proton affinity (review) | 903.2 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 869.3 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
De-protonation reactions
C3H6NO2S- + =
By formula: C3H6NO2S- + H+ = C3H7NO2S
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1395. ± 9.2 | kJ/mol | CIDC | Jones, Bernier, et al., 2007 | gas phase; B |
ΔrH° | 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 |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 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 |
ΔrG° | 1364. ± 13. | kJ/mol | CIDC | O'Hair, Bowie, et al., 1992 | gas phase; B |
UV/Visible spectrum
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Spectrum
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Additional Data
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Source | Johnson, 1971 |
---|---|
Owner | INEP CP RAS, NIST OSRD Collection (C) 2007 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
Origin | INSTITUTE OF ENERGY PROBLEMS OF CHEMICAL PHYSICS, RAS |
Source reference | RAS UV No. 19869 |
Instrument | Unicam SP 500 |
References
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, UV/Visible spectrum, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Sabbah and Minadakis, 1981
Sabbah, R.; Minadakis, C.,
Thermodynamique de substances soufrees. II. Etude thermochimique de la l-cysteine et de la l-methionine,
Thermochim. Acta, 1981, 43, 269-277. [all data]
Becker and Roth, 1934
Becker, G.; Roth, W.A.,
Zur bestimmung der verbrennungswarme von organischen schwefelverbindunge,
Z. Phys. Chem., 1934, 169, 287-296. [all data]
Sunner, 1946
Sunner, S.,
Determination of combustion heats of organo-sulphur compounds,
Svensk. Kim. Tidr., 1946, 58, 71-81. [all data]
Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G.,
Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]
Huffman and Ellis, 1935
Huffman, H.M.; Ellis, E.L.,
Thermal Data. II. The heats of combustion of l-cysteine, of l-cystine, β-thiolactic acid and β,β'-dithiodilactic acid,
J. Am. Chem. Soc., 1935, 57, 41-46. [all data]
Huffman and Ellis, 1935, 2
Huffman, H.M.; Ellis, E.L.,
Thermal data. III. The heat capacities, entropies and free energies of four organic compounds containing sulfur,
J. Am. Chem. Soc., 1935, 57, 46-48. [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]
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]
Johnson, 1971
Johnson, E.A.,
UV atlas of organic compounds, 1971, 5, J2/3. [all data]
Notes
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, UV/Visible spectrum, References
- Symbols used in this document:
Cp,solid Constant pressure heat capacity of solid S°solid,1 bar Entropy of solid at standard conditions (1 bar) ΔcH°solid Enthalpy of combustion of solid at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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