CHEMICAL AND PHYSICAL PROPERTIES
| Physical Description | Colorless or white solid; [HSDB] Colorless crystalline solid; [Sigma-Aldrich MSDS] |
|---|---|
| Color/Form | Colorless crystals |
| Melting Point | 240 dec °C |
| Solubility | 277000 mg/L (at 25 °C) |
| Vapor Pressure | 0.00000207 [mmHg] |
| LogP | -2.49 |
| Stability/Shelf Life | Stable under recommended storage conditions. |
| Optical Rotation | Decomposes 175-178 °C; soluble in water, alcohol, acetone; the aqueous solution is acid; decomposes and oxidizes slowly; hygroscopic. Specific optical rotation: +5.0 °C (5 N HCl) at 25 °C/D; +10.0 °C at 25 °C/D (glacial acetic acid) /Cysteine hydrochloride/ |
| Decomposition | When heated to decomposition it emits very toxic fumes of /sulfur oxides and nitrogen oxides/. |
| Ionization Efficiency | Positive |
| Dissociation Constants | 1.71 |
| Collision Cross Section | 149.57 Ų [M+H]+ [CCS Type: DT, Method: stepped-field] |
| Other Experimental Properties | Readily oxidizes to form a dimeric amino acid, cystine, in which the two cysteines are linked via a disulfide bridge, a common structural feature in proteins. Amino Acids and Proteins, D.M. Greenberg, Ed. (Charles C. Thomas, Springfield, IL, 1951) 950 pp. |
| Chemical Classes | Biological Agents -> Amino Acids and Derivatives |
COMPUTED DESCRIPTORS
| Molecular Weight | 121.16 g/mol |
|---|---|
| XLogP3 | -2.5 |
| Hydrogen Bond Donor Count | 3 |
| Hydrogen Bond Acceptor Count | 4 |
| Rotatable Bond Count | 2 |
| Exact Mass | 121.01974964 g/mol |
| Monoisotopic Mass | 121.01974964 g/mol |
| Topological Polar Surface Area | 64.3 Ų |
| Heavy Atom Count | 7 |
| Formal Charge | 0 |
| Complexity | 75.3 |
| Isotope Atom Count | 0 |
| Defined Atom Stereocenter Count | 1 |
| Undefined Atom Stereocenter Count | 0 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
| Covalently-Bonded Unit Count | 1 |
| Compound Is Canonicalized | Yes |
PRODUCT INTRODUCTION
description
L-cysteine is an optically active form of cysteine having L-configuration. It has a role as a flour treatment agent, a human metabolite and an EC 4.3.1.3 (histidine ammonia-lyase) inhibitor. It is a serine family amino acid, a proteinogenic amino acid, a cysteine and a L-alpha-amino acid. It is a conjugate base of a L-cysteinium. It is a conjugate acid of a L-cysteinate(1-). It is an enantiomer of a D-cysteine. It is a tautomer of a L-cysteine zwitterion.