2-Hydroxybutyric acid
Encyclopedia
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.
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.
Hydroxybutyric acid
Hydroxybutyric acid is a group of four-carbon organic compounds that have both hydroxyl and carboxylic acid functional groups. They can be viewed as derivatives of butyric acid...
with the hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
group on the carbon adjacent to the carboxyl. It is a chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
compound having two enantiomers, D-2-hydroxybutyric acid and L-2-hydroxybutyric acid.
2-Hydroxybutyrate, the conjugate base of 2-hydroxybutyric acid, is produced in mammalian tissues (principally hepatic) that catabolize L-threonine
Threonine
Threonine is an α-amino acid with the chemical formula HO2CCHCHCH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar...
or synthesize glutathione
Glutathione
Glutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...
. Oxidative stress or detoxification demands can dramatically increase the rate of hepatic glutathione synthesis. Under such metabolic stress conditions, supplies of L-cysteine
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
for glutathione synthesis become limiting, so homocysteine
Homocysteine
Homocysteine is a non-protein amino acid with the formula HSCH2CH2CHCO2H. It is a homologue of the amino acid cysteine, differing by an additional methylene group. It is biosynthesized from methionine by the removal of its terminal Cε methyl group...
is diverted from the transmethylation
Transmethylation
Transmethylation is a biologically important organic chemical reaction in which a methyl group is transferred from one compound to another.An example of transmethylation is the recovery of methionine from homocysteine. In order to sustain sufficient reaction rates during metabolic stress, this...
pathway forming methionine into the transsulfuration pathway forming cystathionine. 2-Hydroxybutyrate is released as a byproduct when cystathionine
Cystathionine
Cystathionine is an intermediate in the synthesis of cysteine.It is generated from homocysteine and serine by cystathionine beta synthase.It is cleaved into cysteine and α-ketobutyrate by cystathionine gamma-lyase....
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.