In enzymology, an inosine kinase (EC 2.7.1.73) is an enzyme that catalyzes the chemical reaction
| Inosine kinase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Inosine kinase in Escherichia coli (PDB: 6VWO) | |||||||||
| Identifiers | |||||||||
| EC no. | 2.7.1.73 | ||||||||
| CAS no. | 37237-46-0 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
- ATP + inosine 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
edit- ^ a b c d e Park J, Gupta RS: Adenosine kinase and ribokinase--the RK family of proteins. Cell Mol Life Sci 2008, 65: 2875-2896.
- ^ a b 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.
- ^ 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.
- ^ a b 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.
- ^ 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.
- Pierre KJ, LePage GA (1968). "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. doi:10.3181/00379727-127-32709. PMID 5645030.
