Enables anion binding activity; glutamate decarboxylase activity; and protein N-terminus binding activity. Involved in gamma-aminobutyric acid biosynthetic process and response to xenobiotic stimulus. Located in presynaptic active zone. Used to study diabetes mellitus. Human ortholog(s) of this gene implicated in anxiety disorder; bipolar disorder; developmental and epileptic encephalopathy 89; and schizophrenia. Orthologous to human GAD1 (glutamate decarboxylase 1).