{{Short description|Class of enzymes}} {{protein |Name=ketohexokinase (fructokinase) |caption= Ketohexokinase homodimer, Human |image= 6ul7.jpg |width= 270 |HGNCid=6315 |Symbol=KHK |AltSymbols= |EntrezGene=3795 |OMIM=229800 |RefSeq=NM_006488 |UniProt=P50053 |PDB= |ECnumber=2.7.1.3 |Chromosome=2 |Arm=p |Band=23.3 |LocusSupplementaryData=-23.2 }} {{Infobox enzyme | Name = Ketohexokinase | EC_number = 2.7.1.3 | CAS_number = 9030-50-6 | GO_code = | image = | width = | caption = }} '''Hepatic fructokinase''' (or '''ketohexokinase''') is an enzyme that catalyzes the phosphorylation of fructose to produce fructose-1-phosphate.

:'''ATP''' + 100px|Fru &nbsp;<math>\longrightarrow</math>&nbsp; '''ADP''' + 100px|F1P :ATP + D-fructose → ADP + D-fructose-1-phosphate<ref name="pmid2996495">{{cite journal |vauthors=Bais R, James HM, Rofe AM, Conyers RA |title=The purification and properties of human liver ketohexokinase. A role for ketohexokinase and fructose-bisphosphate aldolase in the metabolic production of oxalate from xylitol |journal=Biochem. J. |volume=230 |issue=1 |pages=53–60 |year=1985 |pmid=2996495 |doi= 10.1042/bj2300053|pmc=1152585}}</ref>

== Isoforms == In humans, ketohexokinase is encoded by the ''KHK'' gene, which produces two isoforms, '''KHK-A''' and '''KHK-C''', through alternative splicing.

* '''KHK-C''' is primarily expressed in the liver, kidney, and intestine. It has a high affinity for fructose (low K<sub>m</sub>) and is responsible for the majority of fructose metabolism. * '''KHK-A''' is ubiquitously expressed in many tissues at low levels. It has a significantly lower affinity for fructose (high K<sub>m</sub>) compared to the C isoform.<ref>{{cite journal | vauthors = Diggle CP, Shires M, Leitch D, Brooke D, Carr IM, Markham AF, Hayward BE, Asipu A, Bonthron DT | title = Ketohexokinase: Expression and Localization of the Principal Fructose-metabolizing Enzyme | journal = Journal of Histochemistry & Cytochemistry | volume = 57 | issue = 8 | pages = 763–774 | date = 2009 | pmid = 19365088 | pmc = 2713076 | doi = 10.1369/jhc.2009.953190 }}</ref>

==References== {{reflist}}

==External links== * {{MeshName|Hepatic+fructokinase}}

{{Fructose and galactose metabolism}} {{Kinases}} {{Enzymes}} {{Portal bar|Biology|border=no}}

Category:EC 2.7.1

{{2.7-enzyme-stub}}