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EC number
CAS number 9026-84-0
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In enzymology, a ribokinase (EC is an enzyme that catalyzes the chemical reaction

ATP + D-ribose ADP + D-ribose 5-phosphate

Thus, the two substrates of this enzyme are ATP and D-ribose, whereas its two products are ADP and D-ribose 5-phosphate.

The systematic name of this enzyme class is ATP:D-ribose 5-phosphotransferase. Other names in common use include deoxyribokinase, ribokinase (phosphorylating), and D-ribokinase. This enzyme participates in pentose phosphate pathway.

Ribokinase (RK) belongs to the phosphofructokinase B (PfkB) family of sugar kinases.[1] Other members of this family (also known as the RK family) include adenosine kinase (AK), inosine-guanosine kinase, fructokinase, and 1-phosphofructokinase.[1][2][3] The members of the PfkB/RK family are identified by the presence of three conserved sequence motifs and the enzymatic activity of this family of protein generally shows a dependence on the presence of pentavalent ions.[1][2][4][5] The conserved NXXE motif, which is a distinctive property of the PfkB family of proteins, is involved in pentavalent ion dependency. The structures of RK and several other PfK family of proteins have been determined from a number of organisms.[6] Despite low sequence similarity between AdK and other PfkB family of proteins, these proteins are quite similar at structural levels.[1]

Structural studies[edit]

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1GQT​, 1RK2​, 1RKA​, 1RKD​, 1RKS​, 1VM7​, and 2FV7​.


  1. ^ a b c d Park J, Gupta RS: Adenosine kinase and ribokinase--the RK family of proteins. Cell Mol Life Sci 2008, 65: 2875-2896.
  2. ^ 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.
  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. ^ 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. ^ Maj, M. and Gupta, R.S. (2001) Pentavalent ion dependancy of the catalytic activity of E. coli Ribokinase. J. Prot. Chem 20: 139-144
  6. ^ 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.
  • Agranoff BW; Brady RO (1956). "Purification and properties of calf liver ribokinase". J. Biol. Chem. 219: 221–229. 
  • GINSBURG A (1959). "A deoxyribokinase from Lactobacillus plantarum". J. Biol. Chem. 234 (3): 481–7. PMID 13641245.