Transaminase that degrades gamma-amino butyric acid (GABA) and uses pyruvate as amino-group acceptor, but not 2-oxoglutarate. Not involved in the interaction with blast fungus. 4-aminobutanoate + pyruvate = L-alanine + succinate semialdehyde 4-aminobutanoate + glyoxylate = glycine + succinate semialdehyde Optimum pH is 8.0. Optimum temperature is 30 degrees Celsius. Expressed in roots, stems and panicles. Strongly up-regulated during leaf senescence. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family.