Which of the following is a key product of the reaction facilitated by AST?

The reaction facilitated by aspartate aminotransferase (AST) primarily involves the transfer of an amino group from aspartate to α-ketoglutarate, resulting in the conversion of these substrates into oxaloacetate and glutamate. This process is significant in amino acid metabolism and the urea cycle, making glutamate a key product of this enzyme-catalyzed reaction. Glutamate plays vital roles in various metabolic pathways, including serving as a neurotransmitter in the brain.

The formation of oxaloacetate does occur during this reaction, but it is not the primary focus when identifying a key product, as AST is named for its action on aspartate, which directly leads to the production of glutamate. The other compounds listed, such as pyruvate and lactate, are involved in different metabolic pathways and are not produced in the reaction catalyzed by AST. Therefore, glutamate stands out as the significant product and an integral part of the metabolic reactions associated with AST.