Record Information
Creation Date2012-05-31 13:00:31 -0600
Update Date2015-09-13 12:56:08 -0600
Secondary Accession Numbers
  • ECMDB00695
Description:Ketoleucine belongs to the class of Branched Fatty Acids. These are fatty acids containing a branched chain. (inferred from compound structure) Ketoleucine is also known by names such as 4-methyl-2-oxopentanoic acid and 2-Oxoisocaproic acid. (PubChem) In E. coli, the enzyme branched-chain amino acid aminotransferase (EC: catalyses the reversible conversion between ketoleucine and L-leucine. (KEGG)
  • α-ketoisocaproate
  • α-ketoisocaproic acid
  • α-oxoisocaproate
  • α-oxoisocaproic acid
  • 2-Keto-4-methyl-pentanoate
  • 2-Keto-4-methyl-pentanoic acid
  • 2-Keto-4-Methylvalerate
  • 2-Keto-4-Methylvaleric acid
  • 2-Ketoisocaproate
  • 2-Ketoisocaproic acid
  • 2-Oxo-4-methylpentanoate
  • 2-Oxo-4-methylpentanoic acid
  • 2-Oxo-4-methylvalerate
  • 2-Oxo-4-methylvaleric acid
  • 2-Oxoisocaproate
  • 2-Oxoisocaproic acid
  • 2-Oxoleucine
  • 2KICA
  • 4-Methyl-2-oxo-Valerate
  • 4-Methyl-2-oxo-Valeric acid
  • 4-Methyl-2-oxopentanoate
  • 4-Methyl-2-oxopentanoic acid
  • a-keto-Isocaproate
  • a-keto-Isocaproic acid
  • A-Ketoisocaproate
  • A-Ketoisocaproic acid
  • A-Ketoisocapronate
  • A-Ketoisocapronic acid
  • A-Oxoisocaproate
  • A-Oxoisocaproic acid
  • Alpha-keto-isocaproate
  • Alpha-keto-isocaproic acid
  • alpha-Ketoisocaproate
  • alpha-Ketoisocaproic acid
  • Alpha-Ketoisocapronate
  • Alpha-Ketoisocapronic acid
  • alpha-Oxoisocaproate
  • alpha-Oxoisocaproic acid
  • Ketoisocaproate
  • Ketoisocaproic acid
  • Methyloxovalerate
  • Methyloxovaleric acid
  • Oxoisocaproate
  • Oxoisocaproic acid
  • α-keto-Isocaproate
  • α-keto-Isocaproic acid
  • α-Ketoisocaproate
  • α-Ketoisocaproic acid
  • α-Ketoisocapronate
  • α-Ketoisocapronic acid
  • α-Oxoisocaproate
  • α-Oxoisocaproic acid
Chemical Formula:C6H10O3
Weight:Average: 130.1418
Monoisotopic: 130.062994186
CAS number:816-66-0
IUPAC Name:4-methyl-2-oxopentanoic acid
Traditional IUPAC Name:ketoisocaproate
Chemical Taxonomy
DescriptionThis compound belongs to the class of chemical entities known as short-chain keto acids and derivatives. These are keto acids with an alkyl chain the contains less than 6 carbon atoms.
KingdomChemical entities
Super ClassOrganic compounds
ClassOrganic acids and derivatives
Sub ClassKeto acids and derivatives
Direct ParentShort-chain keto acids and derivatives
Alternative Parents
  • Branched fatty acid
  • Methyl-branched fatty acid
  • Short-chain keto acid
  • Alpha-keto acid
  • Fatty acyl
  • Alpha-hydroxy ketone
  • 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
Physical Properties
Melting point:8-10 °C
Experimental Properties:
Predicted Properties
Water Solubility6.76 mg/mLALOGPS
pKa (Strongest Acidic)3.53ChemAxon
pKa (Strongest Basic)-9.7ChemAxon
Physiological Charge-1ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area54.37 Å2ChemAxon
Rotatable Bond Count3ChemAxon
Refractivity31.77 m3·mol-1ChemAxon
Polarizability13 Å3ChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Biological Properties
Cellular Locations:Cytoplasm
SMPDB Pathways:
Leucine BiosynthesisPW000811 Pw000811Pw000811 greyscalePw000811 simple
Pantothenate and CoA biosynthesisPW000828 Pw000828Pw000828 greyscalePw000828 simple
Secondary Metabolite: Leucine biosynthesisPW000980 Pw000980Pw000980 greyscalePw000980 simple
Secondary Metabolites: Valine and I-leucine biosynthesis from pyruvatePW000978 Pw000978Pw000978 greyscalePw000978 simple
KEGG Pathways:
  • C5-Branched dibasic acid metabolism ec00660
  • Glucosinolate biosynthesis ec00966
  • Metabolic pathways eco01100
  • Pantothenate and CoA biosynthesis ec00770
  • Valine, leucine and isoleucine biosynthesis ec00290
  • Valine, leucine and isoleucine degradation ec00280
EcoCyc Pathways:
Not Available
Spectrum TypeDescriptionSplash Key
GC-MSGC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (3 TMS)splash10-000i-9400000000-49d055f04bfe1877ac5bView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) (3 TMS)splash10-029j-8930000000-c6c54bf6ee2995a2195bView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies)splash10-0002-1910000000-0ba38257e25873312809View in MoNA
GC-MSGC-MS Spectrum - GC-MS (2 TMS)splash10-0a5c-4930000000-61247369a805fa2a77a7View in MoNA
GC-MSGC-MS Spectrum - GC-MS (1 MEOX; 1 TMS)splash10-000i-9510000000-8bfc5a54e29f65edf361View in MoNA
GC-MSGC-MS Spectrum - GC-MS (1 MEOX; 1 TMS)splash10-00lj-9620000000-aa8409ceb2359d903f38View in MoNA
GC-MSGC-MS Spectrum - GC-MSsplash10-0006-9000000000-e410bce23706f826f8ddView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOFsplash10-000i-9400000000-49d055f04bfe1877ac5bView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOFsplash10-029j-8930000000-c6c54bf6ee2995a2195bView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOFsplash10-0002-1910000000-0ba38257e25873312809View in MoNA
GC-MSGC-MS Spectrum - GC-MSsplash10-0a5c-4930000000-61247369a805fa2a77a7View in MoNA
GC-MSGC-MS Spectrum - GC-MSsplash10-000i-9510000000-8bfc5a54e29f65edf361View in MoNA
GC-MSGC-MS Spectrum - GC-MSsplash10-00lj-9620000000-aa8409ceb2359d903f38View in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOFsplash10-00ks-7930000000-4e9cfd715fa884d30e7fView in MoNA
GC-MSGC-MS Spectrum - GC-EI-TOFsplash10-000i-9500000000-709ebcb57f006703c269View in MoNA
GC-MSGC-MS Spectrum - GC-MS (1 TMS)splash10-0006-9400000000-c4f06cea1e27a2b24660View in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 10V, Positive (Annotated)splash10-0006-9000000000-bed7ac074a60210971e3View in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 25V, Positive (Annotated)splash10-014i-9200000000-2fa08d2b4df406cf63eaView in MoNA
LC-MS/MSLC-MS/MS Spectrum - Quattro_QQQ 40V, Positive (Annotated)splash10-014j-9000000000-045be8e8dca3f93d45baView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 10V, Negativesplash10-004i-0900000000-237fa8ad6bfb929be31eView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 20V, Negativesplash10-004r-9700000000-8d38d24fce78b1ff13e6View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 30V, Negativesplash10-0a59-9000000000-759cfc0817917283d1a5View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 40V, Negativesplash10-0a4l-9000000000-2a068ada71fbe0a5a988View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ (API3000, Applied Biosystems) 50V, Negativesplash10-0a4l-9000000000-58e61e31f3c96d84d799View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-004i-0900000000-237fa8ad6bfb929be31eView in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-004r-9700000000-8d38d24fce78b1ff13e6View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0a59-9000000000-759cfc0817917283d1a5View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0a4l-9000000000-2a068ada71fbe0a5a988View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-QQ , negativesplash10-0a4l-9000000000-58e61e31f3c96d84d799View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-ITFT , negativesplash10-004i-0900000000-556a0d1cf568609752d1View in MoNA
LC-MS/MSLC-MS/MS Spectrum - LC-ESI-IT , negativesplash10-004r-5900000000-20f6923c8ed45e9fa088View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-08gr-7900000000-31021fda89eb6535185fView in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0btm-9200000000-3bf5df4b557ef87267f4View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4i-9000000000-37839bf70647d24b94a4View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-004i-4900000000-796467909d1d4c087a07View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-01ri-9400000000-0abcd021721f32c10e42View in MoNA
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-015l-9000000000-5c33a47dfeb09a182983View in MoNA
1D NMR1H NMR SpectrumNot Available
1D NMR1H NMR SpectrumNot Available
1D NMR13C NMR SpectrumNot Available
2D NMR[1H,13C] 2D NMR SpectrumNot Available
  • Chow LS, Albright RC, Bigelow ML, Toffolo G, Cobelli C, Nair KS: Mechanism of insulin's anabolic effect on muscle: measurements of muscle protein synthesis and breakdown using aminoacyl-tRNA and other surrogate measures. Am J Physiol Endocrinol Metab. 2006 Oct;291(4):E729-36. Epub 2006 May 16. Pubmed: 16705065
  • Hachey DL, Patterson BW, Reeds PJ, Elsas LJ: Isotopic determination of organic keto acid pentafluorobenzyl esters in biological fluids by negative chemical ionization gas chromatography/mass spectrometry. Anal Chem. 1991 May 1;63(9):919-23. Pubmed: 1858984
  • Keseler, I. M., Collado-Vides, J., Santos-Zavaleta, A., Peralta-Gil, M., Gama-Castro, S., Muniz-Rascado, L., Bonavides-Martinez, C., Paley, S., Krummenacker, M., Altman, T., Kaipa, P., Spaulding, A., Pacheco, J., Latendresse, M., Fulcher, C., Sarker, M., Shearer, A. G., Mackie, A., Paulsen, I., Gunsalus, R. P., Karp, P. D. (2011). "EcoCyc: a comprehensive database of Escherichia coli biology." Nucleic Acids Res 39:D583-D590. Pubmed: 21097882
  • Martin PM, Gopal E, Ananth S, Zhuang L, Itagaki S, Prasad BM, Smith SB, Prasad PD, Ganapathy V: Identity of SMCT1 (SLC5A8) as a neuron-specific Na+-coupled transporter for active uptake of L-lactate and ketone bodies in the brain. J Neurochem. 2006 Jul;98(1):279-88. Pubmed: 16805814
  • Mitch WE, Walser M, Sapir DG: Nitrogen sparing induced by leucine compared with that induced by its keto analogue, alpha-ketoisocaproate, in fasting obese man. J Clin Invest. 1981 Feb;67(2):553-62. Pubmed: 7462428
  • Schadewaldt P, Hammen HW, Ott AC, Wendel U: Renal clearance of branched-chain L-amino and 2-oxo acids in maple syrup urine disease. J Inherit Metab Dis. 1999 Aug;22(6):706-22. Pubmed: 10472531
  • Sgaravatti AM, Rosa RB, Schuck PF, Ribeiro CA, Wannmacher CM, Wyse AT, Dutra-Filho CS, Wajner M: Inhibition of brain energy metabolism by the alpha-keto acids accumulating in maple syrup urine disease. Biochim Biophys Acta. 2003 Nov 20;1639(3):232-8. Pubmed: 14636955
  • Sreekumar A, Poisson LM, Rajendiran TM, Khan AP, Cao Q, Yu J, Laxman B, Mehra R, Lonigro RJ, Li Y, Nyati MK, Ahsan A, Kalyana-Sundaram S, Han B, Cao X, Byun J, Omenn GS, Ghosh D, Pennathur S, Alexander DC, Berger A, Shuster JR, Wei JT, Varambally S, Beecher C, Chinnaiyan AM: Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression. Nature. 2009 Feb 12;457(7231):910-4. Pubmed: 19212411
  • van der Werf, M. J., Overkamp, K. M., Muilwijk, B., Coulier, L., Hankemeier, T. (2007). "Microbial metabolomics: toward a platform with full metabolome coverage." Anal Biochem 370:17-25. Pubmed: 17765195
  • Vijayendran, C., Barsch, A., Friehs, K., Niehaus, K., Becker, A., Flaschel, E. (2008). "Perceiving molecular evolution processes in Escherichia coli by comprehensive metabolite and gene expression profiling." Genome Biol 9:R72. Pubmed: 18402659
  • Wang Y, Holmes E, Nicholson JK, Cloarec O, Chollet J, Tanner M, Singer BH, Utzinger J: Metabonomic investigations in mice infected with Schistosoma mansoni: an approach for biomarker identification. Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12676-81. Epub 2004 Aug 16. Pubmed: 15314235
  • Winder, C. L., Dunn, W. B., Schuler, S., Broadhurst, D., Jarvis, R., Stephens, G. M., Goodacre, R. (2008). "Global metabolic profiling of Escherichia coli cultures: an evaluation of methods for quenching and extraction of intracellular metabolites." Anal Chem 80:2939-2948. Pubmed: 18331064
  • Yudkoff M, Daikhin Y, Nissim I, Horyn O, Luhovyy B, Lazarow A, Nissim I: Brain amino acid requirements and toxicity: the example of leucine. J Nutr. 2005 Jun;135(6 Suppl):1531S-8S. Pubmed: 15930465
  • Yurtsever D. (2007). Fatty acid methyl ester profiling of Enterococcus and Esherichia coli for microbial source tracking. Thesis. Villanova University: U.S.A
Synthesis Reference:Not Available
Material Safety Data Sheet (MSDS)Download (PDF)
External Links:
Pubchem Compound ID70
Kegg IDC00233
ChemSpider ID69
Wikipedia IDNot Available
Ligand ExpoCOI


General function:
Involved in transferase activity
Specific function:
An aromatic amino acid + 2-oxoglutarate = an aromatic oxo acid + L-glutamate
Gene Name:
Uniprot ID:
Molecular weight:
An aromatic amino acid + 2-oxoglutarate = an aromatic oxo acid + L-glutamate.
General function:
Involved in magnesium ion binding
Specific function:
Catalyzes the oxidation of 3-carboxy-2-hydroxy-4- methylpentanoate (3-isopropylmalate) to 3-carboxy-4-methyl-2- oxopentanoate. The product decarboxylates to 4-methyl-2 oxopentanoate
Gene Name:
Uniprot ID:
Molecular weight:
(2R,3S)-3-isopropylmalate + NAD(+) = 4-methyl-2-oxopentanoate + CO(2) + NADH.
General function:
Involved in catalytic activity
Specific function:
Acts on leucine, isoleucine and valine
Gene Name:
Uniprot ID:
Molecular weight:
L-leucine + 2-oxoglutarate = 4-methyl-2-oxopentanoate + L-glutamate.
L-isoleucine + 2-oxoglutarate = (S)-3-methyl-2-oxopentanoate + L-glutamate.
L-valine + 2-oxoglutarate = 3-methyl-2-oxobutanoate + L-glutamate.