Transaminase that degrades gamma-amino butyric acid (GABA) and uses pyruvate or glyoxylate as amino-group acceptor. Cannot use beta-alanine, ornithine, acetylornithine, serine, glycine, asparagine, glutamine, glutamate, valine, leucine, isoleucine, methionine, phenylalanine, histidine, lysine, arginine, aspartate, threonine, tyrosine, tryptophan, proline, or cysteine as amino donors. 4-aminobutanoate + pyruvate = L-alanine + succinate semialdehyde 4-aminobutanoate + glyoxylate = glycine + succinate semialdehyde Expressed in leaves, roots, stems, flowers and fruits. Decreased expression in the yellow and red fruits, after the breaker stage. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family.