Difference between revisions of "Hexokinase"
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|<math>0.24 \pm 0.06</math> (n=5)<ref name="Ahn_2009"></ref> | |<math>0.24 \pm 0.06</math> (n=5)<ref name="Ahn_2009"></ref> | ||
|mM | |mM | ||
+ | |} | ||
+ | |||
+ | === Equilibrium constant === | ||
+ | {|class="wikitable" | ||
+ | ! Equilibrium constant | ||
+ | ! Conditions | ||
+ | ! Source | ||
+ | |- | ||
+ | | 4908 | ||
+ | | pH=7, T=25°C | ||
+ | | Voet et al.<ref name="voet">Voet, D., Voet., J.G. and Pratt, C. W. (1999) Fundamentals of biochemistry, Wiley</ref> from Newshole et al. (1973) <ref name="newshole73">Newshole, E.A. and Stuart, C. (1973) Regulation in Metabolism, Wiley</ref>:<br/> | ||
+ | <math>\Delta G' = - 20.9\ kJ.mol^{-1}</math>, <math>Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{20900}{8.31*298.15}) \approx 4908</math> | ||
+ | |- | ||
+ | | 846 | ||
+ | | pH=7, T=25°C | ||
+ | | Lehninger, (1975)<ref name="lehninger2008">David L. Nelson, Michael M. Cox (2008), Lehninger Principles of Biochemistry (5th edn), W. H. Freeman and Company</ref> p 553:<br/> | ||
+ | <math>\Delta G' = - 16.7\ kJ.mol^{-1}</math>, <math>Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{16700}{8.31*298.15}) \approx 845.8</math> | ||
+ | |- | ||
+ | | 890 | ||
+ | | pH=7, T=25°C | ||
+ | | Lehninger, (1975)<ref name="lehninger75">Lehninger, A.L. (1975) Biochemistry (2nd edn), Worth</ref> p 396 | ||
+ | |- | ||
|} | |} | ||
==References== | ==References== | ||
<references/> | <references/> |
Revision as of 12:56, 24 June 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).
Contents
Chemical equation
Rate equation
Without inhibition
Random Bi-Bi Michaelis Menten is used.[1]
With allosteric inhibition
Hexokinase is allosterically inhibited by Glc6P [2]. The rate law taking into account this inhibition is
Parameters
Without inhibition
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
0.04 [3] | HeLa cell line | |||
651[4] | ||||
0.1[1] | mM | |||
1.1[1] | mM | |||
[1] | mM | |||
3.5[1] | mM |
With inhibition
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
0.04 [3] | HeLa cell line | |||
0.1[1] | mM | |||
1.1[1] | mM | |||
[2] | mM |
Parameters with uncertainty
Hexokinase isoenzyme has been reported to vary in different developmental and metabolic status of the cell. In mammalian tissues four isoenzymes of Hexokinase is present [5]. Hexokinase-II has been found to be overexpressed in several first growith cancer cells [3]. Therefore in our model we have considered only the Hexokinase-II kinetic parameter values.
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
Failed to parse (Cannot store math image on filesystem.): 0.02 \pm 0.006 (n=4)[3] | HeLA cell line | |||
(n=5)[6] | mM | SNU449 cell (Human Liver Tissue) | ||
(n=5)[6] | mM | |||
(n=5)[6] | mM |
Equilibrium constant
Equilibrium constant | Conditions | Source |
---|---|---|
4908 | pH=7, T=25°C | Voet et al.[7] from Newshole et al. (1973) [8]: , |
846 | pH=7, T=25°C | Lehninger, (1975)[9] p 553: , |
890 | pH=7, T=25°C | Lehninger, (1975)[10] p 396 |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 (doi)
- ↑ 2.0 2.1 Wilson J E (2003). Isozymes of mammalian hexokinase: structure, subcellular localization and metabolic function. Journal of Experimental Biology, 206, pp. 2049–2057 (doi)
- ↑ 3.0 3.1 3.2 3.3 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) Cite error: Invalid
<ref>
tag; name "Hernandez_2006" defined multiple times with different content - ↑ Arbitrary value
- ↑ Adams V, Kempf W, Hassam S, Briner J. (1995), Determination of hexokinase isoenzyme I and II by RT-PCR: increased hexokinase II isoenzyme in human renal cell carcinoma. J Biochem Mol Med 1995;54:53–58.
- ↑ 6.0 6.1 6.2 Ahn, K.J.; Kim, J.; Yun, M.; Park, J.H.; Lee, J.D.(2009), Enzymatic properties of the N- and C-terminal halves of human hexokinase II, BMB Rep. 42, 350-355.
- ↑ Voet, D., Voet., J.G. and Pratt, C. W. (1999) Fundamentals of biochemistry, Wiley
- ↑ Newshole, E.A. and Stuart, C. (1973) Regulation in Metabolism, Wiley
- ↑ David L. Nelson, Michael M. Cox (2008), Lehninger Principles of Biochemistry (5th edn), W. H. Freeman and Company
- ↑ Lehninger, A.L. (1975) Biochemistry (2nd edn), Worth