Editing Hexokinase (section)

===Hexokinases I, II, and III===
Hexokinases I, II, and III are referred to as low-''K''<sub>m</sub> isoenzymes because of a high affinity for glucose (below 1 mM). Hexokinases I and II follow [[Michaelis-Menten kinetics]] at physiological concentrations of substrates.{{citation needed|date=April 2016}} All three are strongly [[Enzyme inhibitor|inhibited]] by their product, [[glucose-6-phosphate]]. [[Molecular mass]]es are around 100 kDa. Each consists of two similar 50kDa halves, but only in hexokinase II do both halves have functional active sites.

* Hexokinase I/A is found in all mammalian tissues, and is considered a "housekeeping enzyme," unaffected by most physiological, hormonal, and metabolic changes.
* Hexokinase II/B constitutes the principal regulated isoenzyme in many cell types and is increased in many cancers. It is the hexokinase found in muscle and heart. Hexokinase II is also located at the mitochondria outer membrane so it can have direct access to ATP.<ref>{{cite web|url=https://www.uniprot.org/uniprot/P52789#subcellular_location|website=uniprot.org|title=Hexokinase data on Uniprot}}</ref> The relative specific activity of hexokinase II increases with pH at least in a pH range from 6.9 to 8.5.<ref name = "Šimčíková_2019">{{cite journal | vauthors = Šimčíková D, Heneberg P | title = Identification of alkaline pH optimum of human glucokinase because of ATP-mediated bias correction in outcomes of enzyme assays | journal = Scientific Reports | volume = 9 | issue = 1 | pages = 11422 | date = August 2019 | pmid = 31388064 | pmc = 6684659 | doi = 10.1038/s41598-019-47883-1 | bibcode = 2019NatSR...911422S }}</ref>
* Hexokinase III/C is substrate-inhibited by glucose at physiological concentrations. Little is known about the regulatory characteristics of this isoenzyme.