4-aminobutyrate---pyruvate transaminase (, ''aminobutyrate aminotransferase'', ''gamma-aminobutyrate aminotransaminase'', ''gamma-aminobutyrate transaminase'', ''gamma-aminobutyric acid aminotransferase'', ''gamma-aminobutyric acid pyruvate transaminase'', ''gamma-aminobutyric acid transaminase'', ''gamma-aminobutyric transaminase'', ''4-aminobutyrate aminotransferase'', ''4-aminobutyric acid aminotransferase'', ''aminobutyrate transaminase'', ''GABA aminotransferase'', ''GABA transaminase'', ''GABA transferase'', ''POP2 (gene)'') is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

with

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ...

''4-aminobutanoate:pyruvate aminotransferase''. This enzyme is a type of GABA transaminase, which degrades the neurotransmitter GABA. The enzyme catalyses the following

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and break ...

: (1) 4-aminobutanoate +

pyruvate Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO−, is an intermediate in several metabolic pathways throughout the cell. Pyruvic aci ...

\rightleftharpoons

succinate semialdehyde Succinic semialdehyde (SSA) is a GABA metabolite. It is formed from GABA by the action of GABA transaminase and further oxidised to become succinic acid, which enters TCA cycle. See also * Succinic semialdehyde dehydrogenase deficiency * 4-ami ...

+ L-

alanine Alanine (symbol Ala or A), or α-alanine, is an α-amino acid that is used in the biosynthesis of proteins. It contains an amine group and a carboxylic acid group, both attached to the central carbon atom which also carries a methyl group side ...

: (2) 4-aminobutanoate +

glyoxylate Glyoxylic acid or oxoacetic acid is an organic compound. Together with acetic acid, glycolic acid, and oxalic acid, glyoxylic acid is one of the C2 carboxylic acids. It is a colourless solid that occurs naturally and is useful industrially. Str ...

\rightleftharpoons

succinate semialdehyde +

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid ( carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinog ...

This enzyme requires

pyridoxal 5'-phosphate Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent a ...

Clinical significance

Phenylethylidenehydrazine Phenylethylidenehydrazine (PEH), also known as 2-phenylethylhydrazone or β-phenylethylidenehydrazine, is an inhibitor of the enzyme GABA transaminase (GABA-T). It is a metabolite of the antidepressant phenelzine and is responsible for its ele ...

, the active metabolite of

phenelzine Phenelzine, sold under the brand name Nardil, among others, is a non-selective and irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class which is primarily used as an antidepressant and anxiolytic. Along with tranylcypromine and ...

, inhibits gamma-aminobutyric acid transaminase and subsequently increases GABA concentrations in the central nervous system. This may contribute to the notable

anxiolytic An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxie ...

effects of phenelzine.

References

External links

* {{DEFAULTSORT:4-aminobutyrate-pyruvate transaminase EC 2.6.1