In enzymology, 4-aminobutyrate transaminase, also called GABA transaminase or 4-aminobutyrate aminotransferase, or GABA-T, is an enzyme that catalyzes the chemical reaction: 4-aminobutanoate + 2-oxoglutarate ⇌ {\displaystyle \rightleftharpoons } succinate semialdehyde + L-glutamateThus, the two substrates of this enzyme are 4-aminobutanoate and 2-oxoglutarate. Wikipedia