Glutaminase is an important metabolic enzyme responsible for catalyzing the breakdown of glutamine into glutamate and ammonia, a crucial step in nitrogen metabolism. This enzyme is expressed in various cells and tissues, particularly abundant in the liver, and also plays a role in the brain, regulating neurotransmitter balance. The glutaminase family includes multiple homologous enzymes with different tissue-specific expression patterns. Its activity is regulated by pH, metabolite levels, and signaling pathways. Genetic mutations or expression abnormalities are associated with various diseases, including liver diseases, neurological disorders, and cancer. Studying its function and regulatory mechanisms is of significant importance for understanding nitrogen metabolism and related diseases.