Plays an important role in the cellular response to the nitrogen source. URE2 gene plays a major part in the repression of GLN1 and GDH2 genes by glutamine, and is required for the inactivation of glutamine synthetase. URE2 gene product may catalytically inactivate GLN3 in response to an increase in the intracellular concentration of glutamine (By similarity). Homodimer. Belongs to the GST superfamily.