VGLUT substrate glutamate is synthesized from α-KGA by vesicle-bound AAT at the expense of Asp. AAT, aspartate aminotransferase; α-KGA, α-ketoglutarate; Asp, aspartate; Glu, glutamate; OAA, oxaloacetate; 2,3-PDC, 2,3-pirazinedicarboxylate; SV, synaptic vesicle; VGLUT, vesicular glutamate transporter; v-H+-ATPase, v-type proton-pump ATPase.