Biosynthesis of L-glutamate from L-aspartate or L-cysteine (PubMed:21900944). Important regulator of levels of glutamate, the major excitatory neurotransmitter of the vertebrate central nervous system. Acts as a scavenger of glutamate in brain neuroprotection. The aspartate aminotransferase activity is involved in hepatic glucose synthesis during development and in adipocyte glyceroneogenesis. Using L-cysteine as substrate, regulates levels of mercaptopyruvate, an important source of hydrogen sulfide. Mercaptopyruvate is converted into H(2)S via the action of 3-mercaptopyruvate sulfurtransferase (3MST). Hydrogen sulfide is an important synaptic modulator and neuroprotectant in the brain. In addition, catalyzes (2S)-2-aminobutanoate, a by-product in the cysteine biosynthesis pathway (PubMed:27827456). 2-oxoglutarate + L-aspartate = L-glutamate + oxaloacetate 2-oxoglutarate + L-cysteine = 2-oxo-3-sulfanylpropanoate + L-glutamate (2S)-2-aminobutanoate + 2-oxoglutarate = 2-oxobutanoate + L-glutamate 2-oxoglutarate + 3-sulfino-L-alanine = 3-sulfinopyruvate + L-glutamate Homodimer. Genetic variations in GOT1 are associated with low serum aspartate aminotransferase and define the aspartate aminotransferase serum level quantitative trait locus 1 (ASTQTL1) [MIM:614419]. In eukaryotes there are cytoplasmic, mitochondrial and chloroplastic isozymes. Aspartate aminotransferase activity found to be increased in cerebral spinal fluid (CSF) of patients with Alzheimer disease (PubMed:16039064). Fetal serum levels of the enzyme in the umbilical artery and vein are found to be significantly higher than maternal serum levels (PubMed:22633534). Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.