Cysteine

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  • Identifiers

    CAS number
    52-90-4

    Molecular formula
    C3H7NO2S

    SMILES
    C([C@@H](C(=O)O)N)S

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 59.32%
    Sulfurous 59.21%
    Meaty 48.38%
    Savory 40.61%
    Roasted 27.81%
    Cooked 27.08%
    Onion 23.08%
    Cheesy 22.32%
    Garlic 20.36%
    Alliaceous 19.99%

     

    Flavor
    Odorless 60.57%
    Sulfury 34.8%
    Mild 34.2%
    Sulfurous 26.42%
    Bland 25.4%
    Cooked 23.3%
    Yeast 22.79%
    Roasted 22.73%
    Faint 22.21%
    Sweet-like 21.89%

     

    Odor impact est.
    Medium

  • Properties

    XLogP3-AA
    -2.5

    pKa est.
    6.75 (neutral)

    Molecular weight
    121.16 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    277°C

    Melting point expt.

    • 240 dec °C
    • 260 °C decomposes
    • 220 °C

    Flash point

    • 134.28 ˚C est.

    Solubility expt.

    • 277000 mg/L (at 25 °C)
    • Freely soluble in water
    • Freely soluble in alcohol, acetic acid, ammonia water; insoluble in ether, acetone, ethyl acetate, benzene, carbon disulfide, carbon tetrachloride
    • Water solubility (per g/100 g H2O): 28 g/100 mL of solution at 25 °C; 16 g/100 mL of solution at 20 °C
    • 277 mg/mL at 25 °C
    • Very soluble in water and acetic acid; Insoluble in ether, acetone and benzene
    • Soluble (in ethanol)

  • Synonyms

    • L-cysteine
    • 52-90-4
    • cysteine
    • Cystein
    • (R)-Cysteine
    • Thioserine
    • (R)-2-Amino-3-mercaptopropanoic acid
    • Half-cystine
    • L-(+)-Cysteine
    • L-Cystein
    • Cysteinum
    • Cysteine, L-
    • (2R)-2-amino-3-sulfanylpropanoic acid
    • cisteina
    • FREE CYSTEINE
    • beta-Mercaptoalanine
    • Half cystine
    • H-Cys-OH
    • 2-Amino-3-mercaptopropionic acid
    • Cisteinum
    • L-Cys
    • (R)-2-Amino-3-mercaptopropionic acid
    • L-Alanine, 3-mercapto-
    • FEMA No. 3263
    • Cisteinum [Latin]
    • Cysteine [INN]
    • L-2-Amino-3-mercaptopropionic acid
    • Cisteina [Spanish]
    • CCRIS 912
    • L Cysteine
    • NSC-8746
    • L-Zystein
    • alpha-Amino-beta-thiolpropionic acid
    • L-2-Amino-3-mercaptopropanoic acid
    • Cysteinum [INN-Latin]
    • Cisteina [INN-Spanish]
    • beta-Mercaptoalanine, L-
    • CHEBI:17561
    • HSDB 2109
    • (2R)-2-amino-3-mercaptopropanoic acid
    • AI3-26559
    • alpha-Amino-beta-thiolpropionic acid, L-
    • alpha-Amino-beta-mercaptopropanoic acid, L-
    • alpha-Amino-beta-mercaptopropionic acid, L-
    • E 920
    • EINECS 200-158-2
    • Propanoic acid, 2-amino-3-mercapto-, (R)-
    • 2-Amino-3-mercaptopropanoic acid, (R)-
    • Cys
    • E920
    • UNII-K848JZ4886
    • (R)-(+)-Cysteine
    • CHEMBL863
    • K848JZ4886
    • DTXSID8022876
    • EC 200-158-2
    • Cisteinum (Latin)
    • MFCD00064306
    • 4371-52-2
    • Cysteinum (INN-Latin)
    • CYSTEINE (II)
    • CYSTEINE [II]
    • Cisteina (INN-Spanish)
    • E-920
    • CYSTEINE (MART.)
    • CYSTEINE [MART.]
    • Zystein
    • Hcys
    • b-Mercaptoalanine
    • (2R)-2-amino-3-mercaptopropanoate
    • (2R)-2-amino-3-sulfanylpropanoate
    • 3-mercapto-L-Alanine
    • ACETYLCYSTEINE IMPURITY B (EP IMPURITY)
    • ACETYLCYSTEINE IMPURITY B [EP IMPURITY]
    • L-Cysteine from non-animal source
    • Ecolan
    • 345909-32-2 (.xH2O)
    • l-cycteine
    • racemic cysteine
    • L-Cysteine; Acetylcysteine Imp. B (EP); Acetylcysteine Impurity B
    • (2R)-2-amino-3-sulfanylpropanoic acid hydrochloride
    • 2-amino-3-mercaptopropanoate
    • 1ssq
    • S-Alkyl-L-cysteine
    • Ecolan (TN)
    • S-alkyl-L-cysteines
    • L-Cysteine, 97%
    • .beta.-Mercaptoalanine
    • H-Cys-OH HCl H
    • (2R)-2-amino-3-sulfanyl-propanoic acid
    • 1xt8
    • CYSTEINE [HSDB]
    • L-Cysteine (JP18)
    • CYSTEINE [MI]
    • CYSTEINE [VANDF]
    • CYSTEINUM [HPUS]
    • L-CYSTEINE [JAN]
    • bmse000034
    • bmse000975
    • CYSTEINE [WHO-DD]
    • Epitope ID:140791
    • L-CYSTEINE [FHFI]
    • L-CYSTEINE [VANDF]
    • 2-Amino-3-mercaptopropionate
    • DTXCID302876
    • GTPL4782
    • L-Cysteine, >=97%, FG
    • L-2-Amino-3-mercaptopropanoate
    • L-Cysteine - non-animal origin
    • 2-amino-3-mercapto-, (R)-
    • CHEBI:47915
    • AIDS002953
    • (R)-2-Amino-3-mercaptopropanoate
    • HY-Y0337
    • STR02584
    • (R)-2-amino-3-mercapto-Propanoate
    • BDBM50109609
    • s5635
    • (R)-2-Amino-3-mercaptopropanoicacid
    • propanoic acid, 2-amino-3-mercapto-
    • AKOS015854128
    • (+)-2-Amino-3-mercaptopropionic acid
    • CCG-266077
    • CS-W009027
    • DB00151
    • FC16020
    • FC76819
    • (R)-2-amino-3-mercapto-Propanoic acid

  • Applications

    L-Cysteine (CAS 52-90-4) is a sulfur-containing amino acid with extensive applications: in food processing it serves as a dough conditioner, antioxidant and savory flavor precursor, inhibits enzymatic browning in juices and protects vitamin C; in pharmaceuticals it is a glutathione precursor used as a mucolytic, hepatoprotective agent and component of parenteral nutrition; in cosmetics it acts as an antioxidant that shields keratin, reduces hair damage, aids perming/straightening and brightens skin; in molecular biology it functions as a reducing agent for anaerobic culture, promotes protein folding, stabilizes enzymes and chelates metal ions; additionally it is employed in electroplating and metal surface treatment, synthesis of active-pharmaceutical intermediates, fabrication of biomaterials, and as a feed additive that enhances growth and immunity in poultry and aquaculture species.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 0.75
    methanol 5.92
    isopropanol 0.24
    water 172.13
    ethyl acetate 0.06
    n-propanol 0.21
    acetone 12.09
    n-butanol 0.1
    acetonitrile 0.06
    DMF 8.22
    toluene 0.03
    isobutanol 0.06
    1,4-dioxane 0.21
    methyl acetate 0.08
    THF 0.85
    2-butanone 0.27
    n-pentanol 0.13
    sec-butanol 0.06
    n-hexane 0.04
    ethylene glycol 11.84
    NMP 14.48
    cyclohexane 0.05
    DMSO 44.98
    n-butyl acetate 0.18
    n-octanol 0.22
    chloroform 0.02
    n-propyl acetate 0.1
    acetic acid 13.26
    dichloromethane 0.03
    cyclohexanone 0.75
    propylene glycol 2.4
    isopropyl acetate 0.12
    DMAc 4.65
    2-ethoxyethanol 1.8
    isopentanol 0.12
    n-heptane 0.09
    ethyl formate 0.26
    1,2-dichloroethane 0.05
    n-hexanol 0.24
    2-methoxyethanol 3.77
    isobutyl acetate 0.08
    tetrachloromethane 0.04
    n-pentyl acetate 0.28
    transcutol 6.92
    n-heptanol 0.4
    ethylbenzene 0.03
    MIBK 0.38
    2-propoxyethanol 1.61
    tert-butanol 0.55
    MTBE 0.09
    2-butoxyethanol 1.84
    propionic acid 0.63
    o-xylene 0.08
    formic acid 70.31
    diethyl ether 0.06
    m-xylene 0.08
    p-xylene 0.07
    chlorobenzene 0.03
    dimethyl carbonate 0.22
    n-octane 0.05
    formamide 32.89
    cyclopentanone 1.57
    2-pentanone 0.36
    anisole 0.09
    cyclopentyl methyl ether 0.21
    gamma-butyrolactone 1.36
    1-methoxy-2-propanol 1.56
    pyridine 0.15
    3-pentanone 0.17
    furfural 2.9
    n-dodecane 0.03
    diethylene glycol 6.95
    diisopropyl ether 0.07
    tert-amyl alcohol 0.22
    acetylacetone 1.95
    n-hexadecane 0.03
    acetophenone 0.31
    methyl propionate 0.09
    isopentyl acetate 0.22
    trichloroethylene 0.08
    n-nonanol 0.25
    cyclohexanol 0.15
    benzyl alcohol 0.24
    2-ethylhexanol 0.2
    isooctanol 0.37
    dipropyl ether 0.19
    1,2-dichlorobenzene 0.04
    ethyl lactate 0.45
    propylene carbonate 0.57
    n-methylformamide 2.79
    2-pentanol 0.07
    n-pentane 0.03
    1-propoxy-2-propanol 1.07
    1-methoxy-2-propyl acetate 0.56
    2-(2-methoxypropoxy) propanol 3.06
    mesitylene 0.14
    ε-caprolactone 0.46
    p-cymene 0.15
    epichlorohydrin 0.26
    1,1,1-trichloroethane 0.03
    2-aminoethanol 4.51
    morpholine-4-carbaldehyde 5.21
    sulfolane 10.43
    2,2,4-trimethylpentane 0.02
    2-methyltetrahydrofuran 0.19
    n-hexyl acetate 0.3
    isooctane 0.03
    2-(2-butoxyethoxy)ethanol 3.95
    sec-butyl acetate 0.07
    tert-butyl acetate 0.38
    decalin 0.03
    glycerin 13.26
    diglyme 5.36
    acrylic acid 1.9
    isopropyl myristate 0.2
    n-butyric acid 0.47
    acetyl acetate 0.24
    di(2-ethylhexyl) phthalate 0.7
    ethyl propionate 0.07
    nitromethane 6.15
    1,2-diethoxyethane 0.35
    benzonitrile 0.08
    trioctyl phosphate 0.52
    1-bromopropane 0.02
    gamma-valerolactone 3.09
    n-decanol 0.22
    triethyl phosphate 0.28
    4-methyl-2-pentanol 0.13
    propionitrile 0.03
    vinylene carbonate 0.45
    1,1,2-trichlorotrifluoroethane 2.45
    DMS 0.32
    cumene 0.07
    2-octanol 0.21
    2-hexanone 0.23
    octyl acetate 0.28
    limonene 0.19
    1,2-dimethoxyethane 1.29
    ethyl orthosilicate 0.26
    tributyl phosphate 0.46
    diacetone alcohol 1.83
    N,N-dimethylaniline 0.26
    acrylonitrile 0.08
    aniline 0.1
    1,3-propanediol 2.18
    bromobenzene 0.02
    dibromomethane 0.03
    1,1,2,2-tetrachloroethane 0.08
    2-methyl-cyclohexyl acetate 0.39
    tetrabutyl urea 1.08
    diisobutyl methanol 0.3
    2-phenylethanol 0.38
    styrene 0.03
    dioctyl adipate 0.48
    dimethyl sulfate 1.3
    ethyl butyrate 0.18
    methyl lactate 0.88
    butyl lactate 0.9
    diethyl carbonate 0.12
    propanediol butyl ether 3.03
    triethyl orthoformate 0.26
    p-tert-butyltoluene 0.17
    methyl 4-tert-butylbenzoate 1.74
    morpholine 0.26
    tert-butylamine 0.19
    n-dodecanol 0.19
    dimethoxymethane 1.45
    ethylene carbonate 0.25
    cyrene 5.02
    2-ethoxyethyl acetate 0.56
    2-ethylhexyl acetate 0.16
    1,2,4-trichlorobenzene 0.07
    4-methylpyridine 0.11
    dibutyl ether 0.12
    2,6-dimethyl-4-heptanol 0.3
    DEF 0.47
    dimethyl isosorbide 4.57
    tetrachloroethylene 0.16
    eugenol 2.24
    triacetin 1.11
    span 80 3.08
    1,4-butanediol 1.2
    1,1-dichloroethane 0.02
    2-methyl-1-pentanol 0.13
    methyl formate 2.46
    2-methyl-1-butanol 0.07
    n-decane 0.04
    butyronitrile 0.04
    3,7-dimethyl-1-octanol 0.24
    1-chlorooctane 0.05
    1-chlorotetradecane 0.04
    n-nonane 0.04
    undecane 0.03
    tert-butylcyclohexane 0.03
    cyclooctane 0.04
    cyclopentanol 0.3
    tetrahydropyran 0.08
    tert-amyl methyl ether 0.09
    2,5,8-trioxanonane 6.23
    1-hexene 0.04
    2-isopropoxyethanol 0.83
    2,2,2-trifluoroethanol 5.9
    methyl butyrate 0.14

    Scent© AI

1 4

IFRA standard 51

Recommendation
No restriction
Maximum acceptable concentrations in the finished product (%)
Category 1
Products applied to the lips
 No restriction Category 7A
Rinse-off products applied to the hair with some hand contact
 No restriction
Category 2
Products applied to the axillae
 No restriction Category 7B
Leave-on products applied to the hair with some hand contact
 No restriction
Category 3
Products applied to the face/body using fingertips
 No restriction Category 8
Products with significant anogenital exposure
 No restriction
Category 4
Products related to fine fragrance
 No restriction Category 9
Products with body and hand exposure, primarily rinse off
 No restriction
Category 5A
Body lotion products applied to the body using the hands (palms), primarily leave on
 No restriction Category 10A
Household care products with mostly hand contact
 No restriction
Category 5B
Face moisturizer products applied to the face using the hands (palms), primarily leave on
 No restriction Category 10B
Household care products with mostly hand contact, including aerosol/spray products (with potential leave-on skin contact)
 No restriction
Category 5C
Hand cream products applied to the hands using the hands (palms), primarily leave on
 No restriction Category 11A
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate without UV exposure
 No restriction
Category 5D
Baby Creams, baby Oils and baby talc
 No restriction Category 11B
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate with potential UV exposure
 No restriction
Category 6
Products with oral and lip exposure
 No restriction Category 12
Products not intended for direct skin contact, minimal or insignificant transfer to skin
 No restriction