In
enzymology
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
, an inosine kinase () is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that
catalyzes
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
the
chemical reaction
A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...
:ATP + inosine
ADP + IMP
Thus, the two
substrates of this enzyme are
ATP and
inosine
Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond. It was discovered in 1965 in analysis of RNA transferase.
Inosine is commonly found in tRNAs and is ...
, whereas its two
products
Product may refer to:
Business
* Product (business), an item that can be offered to a market to satisfy the desire or need of a customer.
* Product (project management), a deliverable or set of deliverables that contribute to a business solution
...
are
ADP and
IMP
IMP or imp may refer to:
* Imp, a fantasy creature
Arts and entertainment
Music
* IMP (band) a Japanese boy band
Fictional characters
* Imp (She-Ra), a character in ''She-Ra: Princess of Power''
* Imp a character in '' Artemis Fowl: The L ...
.
Inosine kinase belongs to the phosphofructokinase B (PfkB) family of sugar kinases.
[Park J, Gupta RS: Adenosine kinase and ribokinase--the RK family of proteins. Cell Mol Life Sci 2008, 65: 2875-2896.] Other members of this family (also known as the Ribokinase family) include ribokinase (RK) adenosine kinase (AK), fructokinase, and 1-phosphofructokinase.
[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.] The members of the PfkB/RK family are identified by the presence of three conserved sequence motifs.
[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.] 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.
[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.][ Despite low sequence similarity between inosine kinase and other PfkB family of proteins, these proteins are quite similar at structural levels.]purine metabolism
Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms.
Biosynthesis
Purines are biologically synthesized as nucleotides and in particular as ribotides, i.e. bases attached to r ...
.
References
*
EC 2.7.1
Enzymes of unknown structure
{{2.7-enzyme-stub