Adenylate kinase : An Old Enzyme with New Aspects

Adenylate kinase (AK) catalyzes a reversible high-energy phosphoryl transfer reaction between adenine nucleotides. The enzyme contributes to the homeostasis of cellular adenine nucletide composition in addition to the nucleotide biosynthesis. We characterized cDNA and determained the gene structures of three AK isozymes, AK1, AK2 and AK3. The genetic basis of a case of AK1 deficiency was clarified as a single-base substitution in one the patient's chromosomes leading to the Arg to Trp change in the protein. We found that AK1 is localized in neuronal prosesses at high concentrations, which is probably related to a new regulatory function of AK as the high-erergy β-phosphoryl transfer chain from the ASP-synthesizing sites to the ATP-utilizing sites in the cell. AK2 and AK3 are mitochondrial proteins

High-energy phosphate

isozyme

hemolytic anemia

neuronal process

evolution