Hexose-6-phosphate isomerase
The enzyme Hexose-6-phosphate isomerase converts Glucose 6-phosphate (Glc6P) into its isomer Fructose 6-phosphate (Fru6P). Isomers have the same molecular formula, but the atoms of each molecule are arranged differently.
Contents
Chemical reaction
Rate equation
Reversible competitive inhibition with Ery4P, 6PG and FBP. [1]
Substituting with Haldane equation to ensure thermodynamic consistency we have
Parameter values
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
0.4 [1] | HeLa cell line | 3 cell assays | ||
0.9[1] | 1 cell assay | |||
0.4 0.03 mM[1] | mM | 3 cell assays | ||
0.05[1] | mM | 2 cell assays | ||
0.001[1] | mM | Adjusted in the interval based on activity | ||
0.06[1] | mM | Adjusted in the interval based on activity | ||
0.015[1] | mM | Adjusted in the interval based on activity |
Parameters with uncertainty
- The V is measured in the reverse order for the enzyme () in [2] as . The is calculated based on Haldane equation. The same relative percent error for is used to define the uncertainty of this parameter. The value is
- The uncertainty of for HeLa cell line are calculated based on the same proportion of uncertainty for AS-30D cell reported in the paper Marín-Hernández et. al., Modeling cancer glycolysis [1].
- The value of , and are the averaged from the forward and reverse reaction value listed in Table S6 [1].
- The uncertainty for in HeLa cell line is mentioned in the forward reaction as and in the reverse direction as . The mean value is calcualated as and the standard deviation is calculated based on the same ratio mentioned in forward reaction which comes as in mM.
- Same principle is used for . The mean value is and the standard deviation is calculted based on the same ratio of reverse reaction for HeLa cell line; 0.0043
- There are two reported value for ; 0.1[3], 0.06[1]. The mean and standard deviation are calcualted from these two values.
Parameter | Value | Units |
---|---|---|
mM | mM | |
mM | ||
mM | ||
mM | ||
mM |
Equilibrium constant
Equilibrium constant | Conditions | Source |
---|---|---|
0.50 | pH=7, T=25°C | Lehninger, (2008)[4] p 553: , |
0.51 | pH=7, T=25°C | Lehninger, (1975)[5] p 396: Keq(reverse)=1.97 => Keq(forward)=1/1.97=0.51. |
0.41 | pH=7, T=25°C | Voet et al.[6] from Newshole et al. (1973) [7]p 97: , |
- Averaging these values gives
Refences
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et. al. (2011). Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 (doi) Cite error: Invalid
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tag; name "Hernandez2011" defined multiple times with different content - ↑ 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)
- ↑ Marin-Hernandez, A., Gallardo-Perez, J. C., Ralph, S. J., Rodriguez-Enriquez, S. & Moreno-Sanchez, R. (2009), HIF-1α modulates energy metabolism in cancer cells by inducing over-expression of specific glycolytic isoforms. Mini-Rev. Med. Chem. 9, 1084–1101
- ↑ 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
- ↑ 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