Difference between revisions of "Hexokinase"

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The [http://en.wikipedia.org/wiki/Enzyme enzyme] hexokinase phosphorylates (adds a [http://en.wikipedia.org/wiki/Phosphate phosphate] group to) [http://en.wikipedia.org/wiki/Glucose glucose] in the cell's [http://en.wikipedia.org/wiki/Cytoplasm cytoplasm]. In the process, a phosphate group from [http://en.wikipedia.org/wiki/Adenosine_triphosphate Adenosine triphosphate (ATP)] is transferred to glucose producing [http://en.wikipedia.org/wiki/Glucose_6-phosphate glucose 6-phosphate (Glc6P)].
 
The [http://en.wikipedia.org/wiki/Enzyme enzyme] hexokinase phosphorylates (adds a [http://en.wikipedia.org/wiki/Phosphate phosphate] group to) [http://en.wikipedia.org/wiki/Glucose glucose] in the cell's [http://en.wikipedia.org/wiki/Cytoplasm cytoplasm]. In the process, a phosphate group from [http://en.wikipedia.org/wiki/Adenosine_triphosphate Adenosine triphosphate (ATP)] is transferred to glucose producing [http://en.wikipedia.org/wiki/Glucose_6-phosphate glucose 6-phosphate (Glc6P)].
  
== Chemical equation ==
+
=Chemical equation=
  
 
<center><math>Glucose_{in} + ATP \rightleftharpoons Glc6P + ADP</math></center>
 
<center><math>Glucose_{in} + ATP \rightleftharpoons Glc6P + ADP</math></center>
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== Rate equation ==
 
== Rate equation ==
  
===Without inhibitio===
+
===Without inhibition===
 
Random Bi-Bi Michaelis Menten is used.<ref name="Hernandez2011"> Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 ([http://dx.doi.org/10.1016/j.bbabio.2010.11.006 doi])  </ref>
 
Random Bi-Bi Michaelis Menten is used.<ref name="Hernandez2011"> Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 ([http://dx.doi.org/10.1016/j.bbabio.2010.11.006 doi])  </ref>
  

Revision as of 11:18, 4 March 2014

The enzyme hexokinase phosphorylates (adds a phosphate group to) glucose in the cell's cytoplasm. In the process, a phosphate group from Adenosine triphosphate (ATP) is transferred to glucose producing glucose 6-phosphate (Glc6P).

Chemical equation

Glucose_{in} + ATP \rightleftharpoons Glc6P + ADP

Rate equation

Without inhibition

Random Bi-Bi Michaelis Menten is used.[1]

 v = \frac{\frac{V_{mf}}{Km_{Glucose_{in}}K_{ATP}}\Big( [Glucose_{in}][ATP] - \frac{[Glc6P][ADP]}{K_{eq}} \Big)}{1 + \frac{[Glucose_{in}]}{Km_{Glucose_{in}}} + \frac{[ATP]}{K_{ATP}} + \frac{[Glucose_{in}][ATP]}{Km_{Glucose_{in}}K_{ATP}} + \frac{[Glc6P]}{K_{Glc6P}} + \frac{[ADP]}{K_{ADP}} +\frac{[Glc6P][ADP]}{K_{Glc6P}K_{ADP}} + \frac{[Glucose_{in}][ADP]}{K_{Glucose_{in}}K_{ADP}} +\frac{[Glc6P][ATP]}{K_{Glc6P}K_{ATP}} }

Allosteric inhibition

Parameters

Parameter Value Organism Remarks
V_{mf} 0.46 [2] HeLa cell line Vm in U × (mg total cellular protein) at 37^{\circ}C
K_{eq} 1[3]
K_{Glucose_{in}} 9.3
K_{Glucose_{out}} 10[3]

Alternative parameter values

References

  1. Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 (doi)
  2. Marín-Hernández A , Rodríguez-Enríquez S, Vital-González P A, et al. (2006). Determining and understanding the control of glycolysis in fast-growth tumor cells. Flux control by an over-expressed but strongly product-inhibited hexokinase. FEBS J., 273 , pp. 1975–1988(doi)
  3. 3.0 3.1 Arbitrary value