2-Hydroxybutyric acid

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2-Hydroxybutyric acid

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MeSH	2-hydroxybutyric+acid
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Template:Longitem	hydroxybutyrate
Template:Longitem	propionic acid lactic acid 3-hydroxypropionic acid malonic acid butyric acid hydroxypentanoic acid
Template:Longitem	erythrose threose 1,2-butanediol 1,3-butanediol 2,3-butanediol 1,4-butanediol

2-Hydroxybutyric acid, is a hydroxybutyric acid with the hydroxyl group on the carbon adjacent to the carboxyl. It is a chiral compound having two enantiomers, D-2-hydroxybutyric acid and L-2-hydroxybutyric acid. Its conjugate base is known as alpha-hydroxybutyrate and α-hydroxybutyrate.

• Molecular diagram of 2-hydroxybutyric acid, with the central alcohol carbon labeled "(R)"
  d-2-hydroxybutyric acid
• Molecular diagram of 2-hydroxybutyric acid, with the central alcohol carbon labeled "(S)"
  l-2-hydroxybutyric acid

2-Hydroxybutyrate, the conjugate base of 2-hydroxybutyric acid, is produced in mammalian tissues (principally hepatic) that catabolize L-threonine or synthesize glutathione. Oxidative stress or detoxification demands can dramatically increase the rate of hepatic glutathione synthesis. Under such metabolic stress conditions, supplies of L-cysteine for glutathione synthesis become limiting, so homocysteine is diverted from the transmethylation pathway forming methionine into the transsulfuration pathway forming cystathionine. 2-Hydroxybutyrate is released as a byproduct when cystathionine is cleaved to cysteine that is incorporated into glutathione. Chronic shifts in the rate of glutathione synthesis may be reflected by urinary excretion of 2-hydroxybutyrate.

α-hydroxybutyrate may be useful as an early indicator of insulin resistance in non-diabetic subjects. Moreover, elevated serum α-hydroxybutyrate predicts worsening glucose tolerance.