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alpha-Ketoisocaproic acid

α-Ketoisocaproic acid (α-KIC) and its conjugate base, α-ketoisocaproate, are metabolic intermediates in the metabolic pathway for L-leucine.[2]

α-Ketoisocaproic acid
Skeletal formula of alpha-ketoisocaproic acid
IUPAC name
4-Methyl-2-oxopentanoic acid
Systematic IUPAC name
4-Methyl-2-oxopentanoic acid[1]
Other names
4-Methyl-2-oxovaleric acid
3D model (JSmol)
ECHA InfoCard 100.011.304
EC Number
  • 212-435-5
MeSH Alpha-ketoisocaproic+acid
UN number 3265
Molar mass 130.143 g·mol−1
Density 1.055 g cm−3 (at 20 °C)
Melting point 8 to 10 °C (46 to 50 °F; 281 to 283 K)
Boiling point 85 °C (185 °F; 358 K) at 13 mmHg
log P 0.133
Acidity (pKa) 2.651
Basicity (pKb) 11.346
Corrosive C
R-phrases (outdated) R34
S-phrases (outdated) S26, S36/37/39, S45
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Leucine metabolismEdit


  1. ^ CID 70 from PubChem
  2. ^ a b c Wilson JM, Fitschen PJ, Campbell B, Wilson GJ, Zanchi N, Taylor L, Wilborn C, Kalman DS, Stout JR, Hoffman JR, Ziegenfuss TN, Lopez HL, Kreider RB, Smith-Ryan AE, Antonio J (February 2013). "International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB)". Journal of the International Society of Sports Nutrition. 10 (1): 6. doi:10.1186/1550-2783-10-6. PMC 3568064. PMID 23374455.
  3. ^ a b Kohlmeier M (May 2015). "Leucine". Nutrient Metabolism: Structures, Functions, and Genes (2nd ed.). Academic Press. pp. 385–388. ISBN 978-0-12-387784-0. Retrieved 6 June 2016. Energy fuel: Eventually, most Leu is broken down, providing about 6.0kcal/g. About 60% of ingested Leu is oxidized within a few hours ... Ketogenesis: A significant proportion (40% of an ingested dose) is converted into acetyl-CoA and thereby contributes to the synthesis of ketones, steroids, fatty acids, and other compounds
    Figure 8.57: Metabolism of L-leucine