Involved in maintaining the homeostasis of cellular nucleotides by catalyzing the interconversion of nucleoside phosphates (PubMed:19073142, PubMed:19766732, PubMed:23416111, PubMed:24767988). Efficiently phosphorylates AMP and dAMP using ATP as phosphate donor, but phosphorylates only AMP when using GTP as phosphate donor (PubMed:19073142, PubMed:19766732, PubMed:23416111). Also displays broad nucleoside diphosphate kinase activity (PubMed:19073142, PubMed:19766732, PubMed:23416111). Plays a role in controlling cellular ATP levels by regulating phosphorylation and activation of the energy sensor protein kinase AMPK (PubMed:24767988, PubMed:26980435). Plays a protective role in the cellular response to oxidative stress (PubMed:19130895, PubMed:23474458, PubMed:26980435). a ribonucleoside 5'-triphosphate + AMP = a ribonucleoside 5'-diphosphate + ADP a 2'-deoxyribonucleoside 5'-diphosphate + ATP = a 2'-deoxyribonucleoside 5'-triphosphate + ADP a ribonucleoside 5'-diphosphate + ATP = a ribonucleoside 5'-triphosphate + ADP Monomer (Ref.17). Interacts with SLC25A5/ANT2 (PubMed:19130895). Highly expressed in kidney, moderately expressed in heart and liver and weakly expressed in brain. By hypoxia (at protein level). Consists of three domains, a large central CORE domain and two small peripheral domains, NMPbind and LID, which undergo movements during catalysis. The LID domain closes over the site of phosphoryl transfer upon GTP/ATP binding. Assembling and dissambling the active center during each catalytic cycle provides an effective means to prevent GTP/ATP hydrolysis. Belongs to the adenylate kinase family. AK3 subfamily. Some studies have failed to detect adenylate kinase activity (PubMed:11485571, PubMed:19130895). However, kinase activity has been demonstrated in a number of other studies (PubMed:19766732, PubMed:23416111).