Involved in the regulation of glutamine synthetase GlnA, a key enzyme in the process to assimilate ammonia (PubMed:8412694). When cellular nitrogen levels are high, the C-terminal adenylyl transferase inactivates GlnA by covalent transfer of an adenylyl group from ATP to 'Tyr-398' of GlnA, thus reducing its activity (PubMed:4920894, PubMed:9312015). Conversely, when nitrogen levels are low, the N-terminal adenylyl removase (AR) activates GlnA by removing the adenylyl group by phosphorolysis, increasing its activity (PubMed:4893578, PubMed:4920873, PubMed:4934180, PubMed:9312015, PubMed:14766310). The regulatory region of GlnE binds the signal transduction protein PII (GlnB) which indicates the nitrogen status of the cell (PubMed:8412694). [glutamine synthetase]-O(4)-(5'-adenylyl)-L-tyrosine + phosphate = [glutamine synthetase]-L-tyrosine + ADP [glutamine synthetase]-L-tyrosine + ATP = [glutamine synthetase]-O(4)-(5'-adenylyl)-L-tyrosine + diphosphate Can also use Mn(2+). The adenylation activity is stimulated by glutamine and PII (GlnB), and inhibited by 2-oxoglutarate (PubMed:4867671, PubMed:4920894, PubMed:33597, PubMed:9312015). Deadenylation activity is stimulated by PII-UMP (GlnB-UMP) and 2-oxoglutarate, and inhibited by glutamine (PubMed:4893578, PubMed:4934180, PubMed:33597, PubMed:9312015, PubMed:14766310). Optimum pH is between 7.3 and 7.6 (PubMed:4893578, PubMed:4920894). The enzyme is stable between pH 4 and 9 (PubMed:4920894). Monomer. Belongs to the GlnE family.