Aspartate Aminotransferase [Glutamate oxaloacetate transaminase] is a ubiquitous pyridoxal phosphate-dependent enzyme which exists in both mitochondrial and cytosolic forms. The enzyme plays an important role in amino acid metabolism and in the urea and tricarboxylic acid cycles. The 2 isoenzymes are homodimeric. In liver about 80% of the enzyme activity is mitochondrial in origin, whereas in serum the enzyme activity is largely cytosolic. Although the mitochondrial and soluble forms of GOT are coded by different chromosomes, the 2 show close homology in amino acid sequence and were presumably derived from a common ancestral gene.
基因名
GOT1
蛋白名
Aspartate aminotransferase, cytoplasmic
亚基
Homodimer.
亚细胞定位
Cytoplasm.
相似性
Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.
功能
Biosynthesis of L-glutamate from L-aspartate or L-cysteine. 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.