4-aminobutyrate transaminase

4-Aminobutyrate transaminase (also known as GABA transaminase) is an enzyme that plays a crucial role in the metabolism of the neurotransmitter gamma-aminobutyric acid (GABA). This enzyme is responsible for the conversion of GABA to succinate semialdehyde, which is a key step in the GABA shunt pathway.

Function

4-Aminobutyrate transaminase catalyzes the transfer of an amino group from GABA to alpha-ketoglutarate, resulting in the production of succinate semialdehyde and glutamate. This reaction is an important part of the GABA shunt, which is a metabolic pathway that allows for the recycling of GABA and the production of energy in the form of ATP.

Structure

The enzyme is a pyridoxal phosphate (PLP)-dependent transaminase, meaning it requires PLP as a cofactor to function. The structure of 4-aminobutyrate transaminase has been elucidated through X-ray crystallography, revealing a dimeric protein with each subunit containing a PLP-binding site.

Clinical Significance

Dysfunction of 4-aminobutyrate transaminase can lead to disorders in GABA metabolism, which may result in neurological conditions such as epilepsy and schizophrenia. Inhibitors of this enzyme, such as vigabatrin, are used in the treatment of epilepsy by increasing the levels of GABA in the brain.

Related Enzymes

4-Aminobutyrate transaminase is part of a family of enzymes known as aminotransferases, which are involved in the transfer of amino groups between molecules. Other related enzymes include alanine transaminase and aspartate transaminase.

Related Pages

• Gamma-aminobutyric acid
• GABA shunt
• Aminotransferase
• Pyridoxal phosphate