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Short description: Mammalian protein found in Homo sapiens

A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Adenylate kinase 2 is an enzyme that is encoded in humans by the AK2 gene.[1][2][3] The AK2 protein is found in the intermembrane space of the mitochondrion.[4][5]


Adenylate kinases are involved in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. Three isozymes of adenylate kinase, namely 1, 2, and 3, have been identified in vertebrates; this gene encodes isozyme 2. Expression of these isozymes is tissue-specific and developmentally regulated. Isozyme 2 is localized in the mitochondrial intermembrane space and may play a role in apoptosis. Two transcript variants encoding distinct isoforms have been identified for this gene.[3]

AK2 deficiency

Adenylate Kinase 2 (AK2) deficiency in humans causes hematopoietic defects associated with sensorineural deafness.[6][7] Reticular dysgenesis is an autosomal recessive form of human combined immunodeficiency. It is also characterized by an impaired lymphoid maturation and early differentiation arrest in the myeloid lineage. AK2 deficiency results in absent or a large decrease in the expression of proteins. AK2 is specifically expressed in the stria vascularis of the inner ear which indicates why individuals with an AK2 deficiency will have sensorineural deafness.[7]


  1. "Cloning and characterization of cDNA for human adenylate kinase 2A". Biochem Mol Biol Int 39 (4): 833–42. Feb 1997. doi:10.1080/15216549600201931. PMID 8843353. 
  2. "Gene order and localization of enzyme loci on the short arm of chromosome 1". Ann Hum Genet 46 (Pt 4): 329–35. Mar 1983. doi:10.1111/j.1469-1809.1982.tb01583.x. PMID 6961883. 
  3. 3.0 3.1 "Entrez Gene: AK2 adenylate kinase 2". 
  4. "Adenylate kinase 2, a mitochondrial enzyme". Biochem. Genet. 15 (5–6): 477–86. 1977. doi:10.1007/BF00520192. PMID 195572. 
  5. "Release of adenylate kinase 2 from the mitochondrial intermembrane space during apoptosis". FEBS Lett. 447 (1): 10–2. 1999. doi:10.1016/S0014-5793(99)00251-3. PMID 10218571. 
  6. "Reticular dysgenesis (aleukocytosis) is caused by mutations in the gene encoding mitochondrial adenylate kinase 2". Nat. Genet. 41 (1): 101–105. January 2009. doi:10.1038/ng.265. PMID 19043417. 
  7. 7.0 7.1 "Human adenylate kinase 2 deficiency causes a profound haematopoietic defect associated with sensorineural deafness". Nat. Genet. 41 (1): 106–11. January 2009. doi:10.1038/ng.278. PMID 19043416. 

External links

Further reading

  • "Cloning and expression of human adenylate kinase 2 isozymes: differential expression of adenylate kinase 1 and 2 in human muscle tissues". J. Biochem. 123 (1): 47–54. 1998. doi:10.1093/oxfordjournals.jbchem.a021915. PMID 9504408. 
  • "cDNA cloning and tissue-specific expression of the gene encoding human adenylate kinase isozyme 2". Biochim. Biophys. Acta 1395 (1): 34–9. 1998. doi:10.1016/s0167-4781(97)00193-0. PMID 9434148. 
  • "Adenosine triphosphate-adenosine-5'-monophosphate phosphotransferase from normal human liver mitochondria. Isolation, chemical properties, and immunochemical comparison with Duchenne dystrophic serum aberrant adenylate kinase". J. Biol. Chem. 257 (21): 13120–8. 1982. doi:10.1016/S0021-9258(18)33631-7. PMID 6182143.