Probable aminotransferase. Does not have 1-aminocyclopropane-1-carboxylate synthase (ACS) activity, suggesting that it is not involved in ethylene biosynthesis. Homodimer. Expressed in roots. By indole-3-acetic acid (IAA) and cycloheximide (CHX). Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family. Contains a Gln instead of a Glu in position 176 and a Phe residue instead of a Tyr in position 209; these residues being essential in substrate recognition by ACS enzymes.