In enzymology, a ribokinase () is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

that

catalyzes Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

the

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and break ...

:ATP + -ribose ⇌ ADP + -ribose 5-phosphate Thus, the two substrates of this enzyme are

ATP ATP may refer to: Companies and organizations * Association of Tennis Professionals, men's professional tennis governing body * American Technical Publishers, employee-owned publishing company * ', a Danish pension * Armenia Tree Project, non ...

and -ribose, whereas its two products are

ADP Adp or ADP may refer to: Aviation * Aéroports de Paris, airport authority for the Parisian region in France * Aeropuertos del Perú, airport operator for airports in northern Peru * SLAF Anuradhapura, an airport in Sri Lanka * Ampara Air ...

and -ribose 5-phosphate. The

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ...

of this enzyme class is ATP:-ribose 5-phosphotransferase. Other names in common use include deoxyribokinase, ribokinase (phosphorylating), and -ribokinase. This enzyme participates in pentose phosphate pathway. Ribokinase (RK) belongs to the phosphofructokinase B (PfkB) family of sugar kinases. Other members of this family (also known as the RK family) include adenosine kinase (AK), inosine-guanosine kinase, fructokinase, and 1-phosphofructokinase. 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. 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. Despite low sequence similarity between AdK and other PfkB family of proteins, these proteins are quite similar at structural levels.

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , and .

Structural studies

References

Further reading