Biology:Inosine kinase

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Short description: Class of enzymes
Inosine kinase
E. coli guanosine kinase.png
Inosine kinase in Escherichia coli (PDB: 6VWO​)
Identifiers
EC number2.7.1.73
CAS number37237-46-0
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

In enzymology, an inosine kinase (EC 2.7.1.73) is an enzyme that catalyzes the chemical reaction

ATP + inosine [math]\displaystyle{ \rightleftharpoons }[/math] ADP + IMP

Thus, the two substrates of this enzyme are ATP and inosine, whereas its two products are ADP and IMP.

Inosine kinase belongs to the phosphofructokinase B (PfkB) family of sugar kinases.[1] Other members of this family (also known as the Ribokinase family) include ribokinase (RK) adenosine kinase (AK), fructokinase, and 1-phosphofructokinase.[1][2][3] The members of the PfkB/RK family are identified by the presence of three conserved sequence motifs.[1][2][4] The structures of several PfK family of proteins have been determined from a number of organisms and the enzymatic activity of this family of this family of protein shows a dependence on the presence of pentavalent ions.[5][1][4] Despite low sequence similarity between inosine kinase and other PfkB family of proteins, these proteins are quite similar at structural levels.[1] Other names in common use include inosine-guanosine kinase, and inosine kinase (phosphorylating). This enzyme participates in purine metabolism.

References

  1. 1.0 1.1 1.2 1.3 1.4 Park J, Gupta RS: Adenosine kinase and ribokinase--the RK family of proteins. Cell Mol Life Sci 2008, 65: 2875-2896.
  2. 2.0 2.1 Bork P, Sander C, Valencia A: Convergent evolution of similar enzymatic function on different protein folds: the hexokinase, ribokinase, and galactokinase families of sugar kinases. Protein Sci 1993, 2: 31-40.
  3. Spychala J, Datta NS, Takabayashi K, Datta M, Fox IH, Gribbin T, Mitchell BS: Cloning of human adenosine kinase cDNA: sequence similarity to microbial ribokinases and fructokinases. Proc Natl Acad Sci U S A 1996, 93: 1232-1237.
  4. 4.0 4.1 Maj MC, Singh B, Gupta RS: Pentavalent ions dependency is a conserved property of adenosine kinase from diverse sources: identification of a novel motif implicated in phosphate and magnesium ion binding and substrate inhibition. Biochemistry 2002, 41: 4059-4069.
  5. Sigrell JA, Cameron AD, Jones TA, Mowbray SL: Structure of Escherichia coli ribokinase in complex with ribose and dinucleotide determined to 1.8 A resolution: insights into a new family of kinase structures. Structure 1998, 6: 183-193.
  • "Formation of inosine-5'-monophosphate by a kinase in cell-free extracts of Ehrlich ascites cells in vitro". Proc. Soc. Exp. Biol. Med. 127 (2): 432–40. 1968. doi:10.3181/00379727-127-32709. PMID 5645030.