GABA-T

Succinic semialdehyde (SSA) is synthesized in the mitochondria through transamination of y-aminobutyric acid (GABA) by GABA transaminase (GABA-T). Most of the SSA is oxidized by SSA dehydrogenase (SSA-DH) to form succinate, which is used for energy metabolism and results in the end products CO2 + H2O, which are expired. A small portion of SSA (<2%) is converted by SSA reductase (SSA-R) in the cytosol to GHB. GHB may also be oxidized back to SSA by GHB dehydrogenase (GHB-DH). 

GABA is metabolized by GABA-T to form succinic semialdehyde. To conserve the available supply of GABA,... 

CREB CRE-binding protein GABA-T GABA transaminase... 

GABA-T and SSADH enzyme activities may be reliably quantified in leukocytes isolated from whole blood. In both disorders, GABA elevation is expected in CSF, while in GABA-T deficiency, /1-alanine and homocarnosine are also elevated [10]. 

Alanine occupies a central role in intermediary metabolism, primarily as the metabolic breakdown product of pyrimidine (uracil, cytidine) metabolism [7]. Increases in /1-alanine may also be detected in hyper-/ -alaninemia, GABA-T deficiency (see above), and putative combined semialdehyde dehydrogenase deficiency... 

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