InterPro: IPR006259 Adenylate kinase, subfamily

Most members of this family are known or believed to be adenylate kinase.

Adenylate kinase (ADK) EC:2.7.4.3 converts ATP + AMP to ADP + ADP, that is, it uses ATP as a phosphate donor for AMP. Two ADK isozymes have been identified in mammalian cells. These specifically bind AMP and favour binding to ATP over other nucleotide triphosphates (AK1 is cytosolic and AK2 is located in the mitochondria). However, some members accept other nucleotide triphosphates as donors, and may be unable to use ATP, and may fail to complement adenylate kinase mutants. An example of a nucleoside-triphosphate--adenylate kinase (EC:2.7.4.10) is Q9UIJ7, a GTP:AMP phosphotransferase that has been identified in bovine heart and human cells [1] and derived from mitrochondrail GTP AMP that is specific for the phosphorylation of AMP, but can only use GTP or ITP as a substrate [2].This family is designated subfamily rather than equivalog for this reason.

ADK has also been identified in different bacterial species and in yeast [3]. Two further enzymes are known to be related to the ADK family, i.e. yeast uridine monophosphokinase and slime mold UMP-CMP kinase. Within the ADK family there are several conserved regions, including the ATP-binding domains. One of the most conserved areas includes an Arg residue, whose modification inactivates the enzyme, together with an Asp that resides in the catalytic cleft of the enzyme and participates in a salt bridge.