GABA transaminase

In biochemistry and pharmacology, GABA transaminase enzymes comprise a family of transaminases which degrade the neurotransmitter GABA. GABA transaminases include 4-aminobutyrate transaminase, which catalyzes the chemical reaction:

4-aminobutanoate (GABA) + 2-oxoglutarate ⇌ succinate semialdehyde + L-glutamate

and the enzyme 4-aminobutyrate—pyruvate transaminase, which catalyzes the chemical reactions:

(1) 4-aminobutanoate (GABA) + pyruvate ⇌ succinate semialdehyde + L-alanine

(2) 4-aminobutanoate (GABA) + glyoxylate ⇌ succinate semialdehyde + glycine

GABA transaminase is targeted by multiple antiepileptic and analgesic drugs referred to as GABA transaminase inhibitors. Inhibition of this enzyme increases neuronal and synaptic GABA concentrations due to reduced metabolism and degradation of GABA. Inhibitors of the 4-aminobutyrate transaminase isoform include aminooxyacetic acid, gabaculine, phenelzine, phenylethylidenehydrazine (PEH), rosmarinic acid, valproic acid and vigabatrin. Some GABA transaminase inhibitors may be used clinically as anticonvulsants. Other transaminase inhibitors include ethanolamine-O-sulfate (EOS), and L-cycloserine.