Glutaminase C (GLS) is a key enzyme responsible for catalyzing the breakdown of glutamine into glutamate and ammonia, serving as an essential step in nitrogen metabolism and energy production. It is primarily located in the mitochondria, especially abundant in metabolically active tissues such as the liver and brain. GLS plays a role in cell proliferation, energy supply, and neurotransmitter synthesis, contributing to various signaling pathways, including excitatory neurotransmission, by providing glutamate. The expression of the GLS gene is regulated by cellular demands and environmental factors, and changes in its activity and expression levels are associated with a variety of diseases, including tumors, neurodegenerative diseases, and liver disorders. Specific mutations or changes in expression patterns may affect metabolic pathways, influencing the progression and treatment of diseases.