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Record Information
StatusDetected and Quantified
Creation Date2006-08-13 04:36:31 UTC
Update Date2019-01-11 19:17:44 UTC
Secondary Accession Numbers
  • HMDB03771
Metabolite Identification
Common Name2-Methylacetoacetic acid
Description2-Methylacetoacetic acid is a metabolite that has an increased excretion in patients with acetoacetyl-CoA thiolase (EC deficiency (OMIM 607809 , ACAT1; OMIM 100678 , ACAT2; OMIM 604770 , ACAA2; OMIM 607809 ). Thiolases are ubiquitous and important enzymes. Several isoenzymes are known, which can occur in the cytosol (ACAT2), the mitochondria (ACAT1) , or the peroxisomes (ACAA2). Thiolases are CoA-dependent enzymes which catalyze the formation of a carbon-carbon bond in a Claisen condensation step and its reverse reaction via a thiolytic degradation mechanism. mitochondrial acetoacetyl-coenzyme A (CoA) thiolase (T2) is important in the pathways for the synthesis and degradation of ketone bodies as well as for the degradation of 2-methylacetoacetyl-CoA (PMID: 17371050 , 14518824 , 9744475 , 9001814 ). Moreover, 2-methylacetoacetic acid is found to be associated with beta-ketothiolase deficiency, which is also an inborn error of metabolism.
2-Methyl-3-oxo-butyric acidChEBI
(+/-)-2-methyl-3-oxobutanoic acidHMDB
2-Acetylpropionic acidHMDB
2-Methyl-3-ketobutyric acidHMDB
2-Methyl-3-oxo-butanoic acidHMDB
2-Methyl-3-oxobutanoic acidHMDB
2-Methyl-3-oxobutyric acidHMDB
2-Methyl-acetoacetic acidHMDB
3-oxo-2-Methylbutyric acidHMDB
a-Methylacetoacetic acidHMDB
alpha-Methylacetoacetic acidHMDB
Chemical FormulaC5H8O3
Average Molecular Weight116.1152
Monoisotopic Molecular Weight116.047344122
IUPAC Name2-methyl-3-oxobutanoic acid
Traditional Nameacetopropionic acid
CAS Registry Number2382-59-4
InChI Identifier
Chemical Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as short-chain keto acids and derivatives. These are keto acids with an alkyl chain the contains less than 6 carbon atoms.
KingdomOrganic compounds
Super ClassOrganic acids and derivatives
ClassKeto acids and derivatives
Sub ClassShort-chain keto acids and derivatives
Direct ParentShort-chain keto acids and derivatives
Alternative Parents
  • Beta-keto acid
  • Branched fatty acid
  • Methyl-branched fatty acid
  • Short-chain keto acid
  • Beta-hydroxy ketone
  • Fatty acyl
  • 1,3-dicarbonyl compound
  • Ketone
  • Carboxylic acid derivative
  • Carboxylic acid
  • Monocarboxylic acid or derivatives
  • Carbonyl group
  • Hydrocarbon derivative
  • Organic oxygen compound
  • Organooxygen compound
  • Organic oxide
  • Aliphatic acyclic compound
Molecular FrameworkAliphatic acyclic compounds
External Descriptors


Biological location:


Naturally occurring process:


Industrial application:

Biological role:

Physical Properties
Experimental Properties
Melting PointNot AvailableNot Available
Boiling PointNot AvailableNot Available
Water SolubilityNot AvailableNot Available
LogPNot AvailableNot Available
Predicted Properties
Water Solubility94.9 g/LALOGPS
pKa (Strongest Acidic)4.17ChemAxon
pKa (Strongest Basic)-7.5ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area54.37 ŲChemAxon
Rotatable Bond Count2ChemAxon
Refractivity27.11 m³·mol⁻¹ChemAxon
Polarizability11.09 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectrum TypeDescriptionSplash Key
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-0006-9000000000-4522174bd24a6b761d39View in MoNA
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-00fr-8900000000-fee1d74840bb965bcfe4View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-014i-9600000000-d0862c2daa04fdcefc78View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0g6s-9100000000-90a265e5eaa63e5ef5e0View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0pb9-9000000000-661f491ab0f15426947bView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-014i-6900000000-54e32b9b92df94a1fe9eView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-00di-9000000000-e95b19f182cd6fb67e1dView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0l6r-9000000000-82441ad6584e10cb7f43View in MoNA
Biological Properties
Cellular Locations
  • Extracellular
  • Membrane
Biospecimen Locations
  • Blood
  • Urine
Tissue LocationsNot Available
Normal Concentrations
BloodExpected but not Quantified Not AvailableNot Available
    UrineDetected and Quantified0 umol/mmol creatinineAdult (>18 years old)Both
    UrineDetected and Quantified<2 umol/mmol creatinineChildren (1 - 18 years old)Both
      • BC Children's Hos...
    Abnormal Concentrations
    UrineDetected and Quantified8030 umol/mmol creatinineChildren (1-13 years old)Not SpecifiedBeta-ketothiolase deficiency details
    UrineDetected and Quantified3368 umol/mmol creatinineChildren (1-13 years old)Not Specified
    Beta-ketothiolase deficiency
    UrineDetected and Quantified325.0 (0.0-650.0) umol/mmol creatinineChildren (1-13 years old)BothBeta-Ketothiolase deficiency
      • MetaGene: Metabol...
    Associated Disorders and Diseases
    Disease References
    Beta-ketothiolase deficiency
    1. Fontaine M, Briand G, Ser N, Armelin I, Rolland MO, Degand P, Vamecq J: Metabolic studies in twin brothers with 2-methylacetoacetyl-CoA thiolase deficiency. Clin Chim Acta. 1996 Nov 15;255(1):67-83. [PubMed:8930414 ]
    2. G.Frauendienst-Egger, Friedrich K. Trefz (2017). MetaGene: Metabolic & Genetic Information Center (MIC: METAGENE consortium.
    Associated OMIM IDs
    • 203750 (Beta-ketothiolase deficiency)
    DrugBank IDNot Available
    Phenol Explorer Compound IDNot Available
    FoodDB IDFDB023226
    KNApSAcK IDNot Available
    Chemspider ID133090
    KEGG Compound IDNot Available
    BioCyc IDNot Available
    BiGG IDNot Available
    Wikipedia LinkNot Available
    METLIN IDNot Available
    PubChem Compound150996
    PDB IDNot Available
    ChEBI ID37079
    Synthesis ReferenceMiddleton B; Bartlett K The synthesis and characterisation of 2-methylacetoacetyl coenzyme A and its use in the identification of the site of the defect in 2-methylacetoacetic and 2-methyl-3-hydroxybutyric aciduria. Clinica chimica acta; international journal of clinical chemistry (1983), 128(2-3), 291-305.
    Material Safety Data Sheet (MSDS)Not Available
    General References
    1. Haapalainen AM, Merilainen G, Pirila PL, Kondo N, Fukao T, Wierenga RK: Crystallographic and kinetic studies of human mitochondrial acetoacetyl-CoA thiolase: the importance of potassium and chloride ions for its structure and function. Biochemistry. 2007 Apr 10;46(14):4305-21. Epub 2007 Mar 20. [PubMed:17371050 ]
    2. Fukao T, Nakamura H, Song XQ, Nakamura K, Orii KE, Kohno Y, Kano M, Yamaguchi S, Hashimoto T, Orii T, Kondo N: Characterization of N93S, I312T, and A333P missense mutations in two Japanese families with mitochondrial acetoacetyl-CoA thiolase deficiency. Hum Mutat. 1998;12(4):245-54. [PubMed:9744475 ]
    3. Fukao T, Zhang GX, Sakura N, Kubo T, Yamaga H, Hazama A, Kohno Y, Matsuo N, Kondo M, Yamaguchi S, Shigematsu Y, Kondo N: The mitochondrial acetoacetyl-CoA thiolase (T2) deficiency in Japanese patients: urinary organic acid and blood acylcarnitine profiles under stable conditions have subtle abnormalities in T2-deficient patients with some residual T2 activity. J Inherit Metab Dis. 2003;26(5):423-31. [PubMed:14518824 ]
    4. Fukao T, Kodama A, Aoyanagi N, Tsukino R, Uemura S, Song XQ, Watanebe H, Kuhara T, Matsumoto I, Orii T, Kondo N: Mild form of beta-ketothiolase deficiency (mitochondrial acetoacetyl-CoA thiolase deficiency) in two Japanese siblings: identification of detectable residual activity and cross-reactive material in EB-transformed lymphocytes. Clin Genet. 1996 Oct;50(4):263-6. [PubMed:9001814 ]