2-Keto-4-methylthiobutyric acid

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  • Identifiers

    CAS number
    583-92-6

    Molecular formula
    C5H8O3S

    SMILES
    CSCCC(=O)C(=O)O

  • Odor profile

    Fragrance
    Sulfurous 74.65%
    Meaty 54.52%
    Cheesy 48.72%
    Roasted 47.54%
    Savory 46.22%
    Vegetable 42.12%
    Sweet 41.77%
    Onion 39.56%
    Cabbage 38.26%
    Cooked 36.4%

     

    Flavor
    Cooked 29.52%
    Odorless 28.97%
    Cabbage 27.44%
    Nutty 25.15%
    Sour 23.89%
    Acidic 22.65%
    Creamy 22.44%
    Sulfury 22.29%
    Roasted 21.73%
    Caramel 21.62%

     

    Odor impact est.
    High

  • Properties

    XLogP3-AA
    0.3

    pKa est.
    5.83 (weak acid)

    Molecular weight
    148.18 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    278°C

    Flash point

    • 128.45 ˚C est.

  • Synonyms

    • 4-Methylthio-2-oxobutanoic acid
    • 583-92-6
    • 4-(Methylsulfanyl)-2-oxobutanoic acid
    • 2-keto-4-methylthiobutyric acid
    • alpha-Oxomethionine
    • alpha-Ketomethionine
    • 4-(Methylthio)-2-oxobutanoic acid
    • 2-oxo-4-methylthiobutanoate
    • 4-methylthio-2-oxobutanoate
    • 4-Methylmercapto-2-oxobutyrate
    • 2-Oxo-4-thiomethylbutyric acid
    • alpha-Keto-gamma-methiolbutyrate
    • gamma-Methiol-keto-butyric acid
    • S-Methyl-alpha-ketobutyric acid
    • 4-Methylthio-2-ketobutyric acid
    • 2-Ketothiomethylbutyric acid
    • 2-Keto-4-thiomethylbutyrate
    • 4-methylsulfanyl-2-oxobutanoic acid
    • alpha-Oxo-gamma-methylthiobutyric acid
    • 2-oxo-4-methylthiobutanoic acid
    • Butanoic acid, 4-(methylthio)-2-oxo-
    • 2-Keto-4-methylthiobutanoic acid
    • 4-methylthio-2-oxobutyric acid
    • CHEBI:33574
    • 4-(Methylthio)-2-oxobutyric acid
    • .ALPHA.-KETOMETHIONINE
    • 2-oxo-4-methylthio-butanoic acid
    • DTXSID50207027
    • 2-keto-4-(methylthio)butyric acid
    • 2-keto-4-methylthiobutyrate
    • 2-oxomethionine
    • 286060413U
    • ketomethiobutyrate
    • .ALPHA.-KETO-METHYLTHIOBUTYRIC ACID
    • 2-OXO-4-(METHYLTHIO)BUTANOIC ACID
    • 2-ketomethiobutyrate
    • KMTB
    • .ALPHA.-KETO-4-(METHYLTHIO)BUTYRIC ACID
    • .ALPHA.-KETO-.GAMMA.-(METHYLTHIO)BUTYRIC ACID
    • .ALPHA.-OXO-.GAMMA.-(METHYLTHIO)-N-BUTYRIC ACID
    • BUTYRIC ACID, .GAMMA.-METHYLMERCAPTO-.ALPHA.-OXO-
    • 4-methylthio-2-oxobutyrate
    • 4-methylthio-2-ketobutyrate
    • 4-methylthio-2-ketobutanoate
    • KMT
    • 4-(methyl thio)-2-oxobutyric acid
    • 4-(methylthio)-2-oxo-butanoic acid
    • UNII-286060413U
    • ketomethiobutyric acid
    • keto-4-methylthiobutyrate
    • alpha-Keto-methiolbutyric acid
    • SCHEMBL126896
    • 2-Oxo-4-methylthiobutyric acid
    • CHEMBL1233860
    • 4-Methylthio-2-ketobutanoic acid
    • DTXCID50129518
    • SXFSQZDSUWACKX-UHFFFAOYSA-N
    • BDBM154571
    • 4-Methylmercapto-2-oxobutyric acid
    • Butanoic acid, 4-methylthio-2-oxo-
    • LMFA01060170
    • AKOS006222790
    • Butyric acid, 4-(methylthio)-2-oxo-
    • DB02238
    • 4-Methylthio 2-oxobutyric acid (MTOB)
    • ALPHA-KETO-METHYLTHIOBUTYRIC ACID
    • 4-(Methylsulfanyl)-2-oxobutanoic acid #
    • alpha-keto-gamma-(methylthio)butyric acid
    • PD008115
    • NS00014699
    • ALPHA-KETO-4-(METHYLTHIO)BUTYRIC ACID
    • C01180
    • EN300-1600874
    • ALPHA-OXO-GAMMA-(METHYLTHIO)-N-BUTYRIC ACID
    • BUTYRIC ACID, GAMMA-METHYLMERCAPTO-ALPHA-OXO-
    • Q27093278
    • BDBE5218-EF11-4F3E-94DD-6891BAC49A24

  • Applications

    2-Keto-4-methylthiobutyric acid (CAS 583-92-6) is an alpha-keto acid bearing a methylthio substituent and is primarily recognized as an intermediate in methionine biosynthesis and related sulfur-containing amino acid chemistry. In industrial amino acid production by fermentation and chemical synthesis, it is used as a substrate for transaminase-catalyzed reactions to produce methionine or methionine derivatives, and also as a key building block for sulfur-containing compounds. In enzymology research, it serves as a common substrate in assays of aminotransferase activity and other methionine-related metabolic pathways. In certain experimental biological systems, it can act as a precursor to ethylene under photochemical or oxidative conditions, making it of interest in plant and microbial physiology studies. Additionally, it is used as a reference standard for analytical methods involving keto acids and amino acid analogs.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 53.37
    methanol 75.07
    isopropanol 29.77
    water 12.19
    ethyl acetate 10.27
    n-propanol 29.74
    acetone 23.19
    n-butanol 26.38
    acetonitrile 7.07
    DMF 104.87
    toluene 1.37
    isobutanol 16.85
    1,4-dioxane 29.63
    methyl acetate 12.14
    THF 43.56
    2-butanone 12.65
    n-pentanol 19.47
    sec-butanol 20.34
    n-hexane 0.54
    ethylene glycol 50.68
    NMP 156.9
    cyclohexane 1.27
    DMSO 208.59
    n-butyl acetate 13.68
    n-octanol 15.52
    chloroform 3.24
    n-propyl acetate 8.34
    acetic acid 66.84
    dichloromethane 6.68
    cyclohexanone 35.51
    propylene glycol 37.77
    isopropyl acetate 8.45
    DMAc 89.69
    2-ethoxyethanol 57.86
    isopentanol 22.09
    n-heptane 1.36
    ethyl formate 15.83
    1,2-dichloroethane 8.21
    n-hexanol 21.8
    2-methoxyethanol 105.65
    isobutyl acetate 5.08
    tetrachloromethane 1.04
    n-pentyl acetate 13.04
    transcutol 139.18
    n-heptanol 18.6
    ethylbenzene 2.54
    MIBK 10.07
    2-propoxyethanol 52.05
    tert-butanol 36.16
    MTBE 7.67
    2-butoxyethanol 47.08
    propionic acid 34.97
    o-xylene 3.75
    formic acid 79.78
    diethyl ether 4.57
    m-xylene 2.8
    p-xylene 3.3
    chlorobenzene 3.24
    dimethyl carbonate 8.81
    n-octane 0.8
    formamide 107.14
    cyclopentanone 43.78
    2-pentanone 12.35
    anisole 7.86
    cyclopentyl methyl ether 11.88
    gamma-butyrolactone 63.34
    1-methoxy-2-propanol 64.79
    pyridine 13.19
    3-pentanone 6.73
    furfural 67.5
    n-dodecane 0.88
    diethylene glycol 74.03
    diisopropyl ether 2.72
    tert-amyl alcohol 27.65
    acetylacetone 25.27
    n-hexadecane 0.95
    acetophenone 17.06
    methyl propionate 11.6
    isopentyl acetate 14.71
    trichloroethylene 11.46
    n-nonanol 14.81
    cyclohexanol 19.97
    benzyl alcohol 18.17
    2-ethylhexanol 13.83
    isooctanol 15.03
    dipropyl ether 6.2
    1,2-dichlorobenzene 6.08
    ethyl lactate 13.67
    propylene carbonate 32.22
    n-methylformamide 52.76
    2-pentanol 13.71
    n-pentane 0.59
    1-propoxy-2-propanol 37.26
    1-methoxy-2-propyl acetate 23.34
    2-(2-methoxypropoxy) propanol 46.74
    mesitylene 3.26
    ε-caprolactone 41.36
    p-cymene 5.84
    epichlorohydrin 41.64
    1,1,1-trichloroethane 3.09
    2-aminoethanol 60.43
    morpholine-4-carbaldehyde 109.32
    sulfolane 137.43
    2,2,4-trimethylpentane 0.68
    2-methyltetrahydrofuran 23.1
    n-hexyl acetate 17.83
    isooctane 0.63
    2-(2-butoxyethoxy)ethanol 70.05
    sec-butyl acetate 5.8
    tert-butyl acetate 14.39
    decalin 1.31
    glycerin 71.64
    diglyme 95.19
    acrylic acid 39.97
    isopropyl myristate 8.57
    n-butyric acid 32.47
    acetyl acetate 10.01
    di(2-ethylhexyl) phthalate 15.91
    ethyl propionate 7.13
    nitromethane 65.88
    1,2-diethoxyethane 18.36
    benzonitrile 10.47
    trioctyl phosphate 12.77
    1-bromopropane 2.32
    gamma-valerolactone 82.99
    n-decanol 11.79
    triethyl phosphate 9.76
    4-methyl-2-pentanol 9.75
    propionitrile 5.57
    vinylene carbonate 26.5
    1,1,2-trichlorotrifluoroethane 53.57
    DMS 14.95
    cumene 3.54
    2-octanol 10.74
    2-hexanone 8.95
    octyl acetate 12.75
    limonene 7.91
    1,2-dimethoxyethane 41.27
    ethyl orthosilicate 9.03
    tributyl phosphate 12.13
    diacetone alcohol 41.04
    N,N-dimethylaniline 11.82
    acrylonitrile 11.01
    aniline 7.55
    1,3-propanediol 75.67
    bromobenzene 2.27
    dibromomethane 3.7
    1,1,2,2-tetrachloroethane 12.77
    2-methyl-cyclohexyl acetate 17.3
    tetrabutyl urea 23.19
    diisobutyl methanol 10.35
    2-phenylethanol 21.57
    styrene 2.2
    dioctyl adipate 17.63
    dimethyl sulfate 25.47
    ethyl butyrate 10.24
    methyl lactate 24.94
    butyl lactate 20.54
    diethyl carbonate 7.63
    propanediol butyl ether 52.39
    triethyl orthoformate 9.99
    p-tert-butyltoluene 5.63
    methyl 4-tert-butylbenzoate 31.55
    morpholine 43.87
    tert-butylamine 13.62
    n-dodecanol 9.22
    dimethoxymethane 27.87
    ethylene carbonate 18.83
    cyrene 61.37
    2-ethoxyethyl acetate 22.0
    2-ethylhexyl acetate 10.6
    1,2,4-trichlorobenzene 9.48
    4-methylpyridine 10.3
    dibutyl ether 6.49
    2,6-dimethyl-4-heptanol 10.35
    DEF 28.35
    dimethyl isosorbide 69.69
    tetrachloroethylene 9.5
    eugenol 36.35
    triacetin 25.39
    span 80 45.79
    1,4-butanediol 35.4
    1,1-dichloroethane 2.89
    2-methyl-1-pentanol 17.96
    methyl formate 32.93
    2-methyl-1-butanol 17.63
    n-decane 1.04
    butyronitrile 6.96
    3,7-dimethyl-1-octanol 15.1
    1-chlorooctane 4.0
    1-chlorotetradecane 2.32
    n-nonane 0.91
    undecane 0.95
    tert-butylcyclohexane 1.06
    cyclooctane 0.72
    cyclopentanol 27.71
    tetrahydropyran 12.13
    tert-amyl methyl ether 7.94
    2,5,8-trioxanonane 81.85
    1-hexene 1.57
    2-isopropoxyethanol 33.07
    2,2,2-trifluoroethanol 30.11
    methyl butyrate 11.73

    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