Transaminase converting glutamate 1-semialdehyde (GSA) to 5-aminolevulinate (ALA). Involved in the biosynthesis of tetrapyrroles. (S)-4-amino-5-oxopentanoate = 5-aminolevulinate Can use both pyridoxamine 5'-phosphate (PMP) and pyridoxal 5'-phosphate (PLP) as cofactors. Porphyrin-containing compound metabolism; protoporphyrin-IX biosynthesis; 5-aminolevulinate from L-glutamyl-tRNA(Glu): step 2/2. Porphyrin-containing compound metabolism; chlorophyll biosynthesis. Homodimer. Expressed in leaf primordia and shoot apical meristems (SAM). Suppresses partially the ENF1 disruption pleiotropic developmental phenotypes, including the suppression of the abnormal patterning of the adaxial-abaxial-related gene expression in leaf primordia. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family. HemL subfamily.