| Modification Notes |
Adenylate kinases 1-5 (designated AK1-5) are a set of enzymes that regulate the phosphorylation state of intracellular adenine nucleotides, which are the principal high-energy phosphoryl-carrying molecules in living cells. AKs influence metabolic signals, which include gene expression, ion channel activity and protein kinase-mediated signaling, by catalyzing phosphoryl transfer between adenine nucleotides (AMP, ADP, ATP). Inherited mutations leading to AK deficiencies in erythrocytes have been implicated in hemolytic anemia. AK5 (also designated AK6 or ATP-AMP transphosphorylase) is expressed in the brain and localizes to the cytosol. Like other AKs, it contains an NMP-binding domain, a lid domain and a P-loop. AK5 phosphorylates dAMP and AMP with equal efficiency. It is similar to UMP/CMP kinase and the two enzymes overlap in substrate specificity. Human AK5 occurs in three isoforms: one short isoform (AK5) and two long isoforms (AK5-1 and AK5-2). |