Editing Glycolysis (section)

====Hexokinase and glucokinase====
[[File:Hexokinase B 1IG8 wpmp.png|thumb|right|[[Yeast]] [[hexokinase]] B ({{PDB|1IG8}})]]
All cells contain the enzyme [[hexokinase]], which catalyzes the conversion of glucose that has entered the cell into [[glucose-6-phosphate]] (G6P). Since the cell membrane is impervious to G6P, hexokinase essentially acts to transport glucose into the cells from which it can then no longer escape.  Hexokinase is inhibited by high levels of G6P in the cell. Thus the rate of entry of glucose into cells partially depends on how fast G6P can be disposed of by glycolysis, and by [[Glycogenesis|glycogen synthesis]] (in the cells which store glycogen, namely liver and muscles).<ref name=stryer /><ref name=voet>{{cite book | vauthors = Voet D, Voet JG, Pratt CW |title=Fundamentals of Biochemistry | edition = 2nd |publisher=John Wiley and Sons, Inc. |year=2006 |pages=[https://archive.org/details/fundamentalsofbi00voet_0/page/547 547, 556] |isbn=978-0-471-21495-3 |url=https://archive.org/details/fundamentalsofbi00voet_0/page/547 }}</ref>

[[Glucokinase]], unlike hexokinase, is not inhibited by G6P. It occurs in liver cells, and will only phosphorylate the glucose entering the cell to form G6P, when the glucose in the  blood is abundant. This being the first step in the glycolytic pathway in the liver, it therefore imparts an additional layer of control of the glycolytic pathway in this organ.<ref name=stryer />