Triosephosphate isomerase
This enzyme rapidly inter-converts the molecules Dihydroxyacetone phosphate (DHAP) and Glyceraldehyde 3-phosphate (Gly3P). Gly3P is removed as soon as it is formed to be used in the next step of glycolysis.
Contents
Chemical equation
![DHAP \rightleftharpoons Gly3P](/wiki/images/math/3/9/2/392d952f618b5b87a5ac1930dc117df5.png)
Rate equation
Reversible Michaelis-Menten is used [1]
![v = \frac{ V_{mf}\frac{[DHAP]}{K_{DHAP}} - V_{mr}\frac{[Gly3P]}{K_{Gly3P}} }{1 + \frac{[DHAP]}{K_{DHAP}} + \frac{[Gly3P]}{K_{Gly3P}} }](/wiki/images/math/c/4/3/c43ea2245f63ddca8689602949bdf9f4.png)
Modified rate law considering thermodynamic constant is
![v = \frac{ V_{mf}\frac{[DHAP]}{K_{DHAP}}\left(1 - \frac{[Gly3P]}{K_{eq}[DHAP]} \right)}{1 + \frac{[DHAP]}{K_{DHAP}} + \frac{[Gly3P]}{K_{Gly3P}} }](/wiki/images/math/0/a/2/0a21e55dde0aa7699f6d0a6b766641a7.png)
Paramters
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
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5 [1] | ![]() |
Hela cell line | |
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42[2] | ![]() | ||
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0.51[1] | mM | ||
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1.6[1] | mM |
Parameters with uncertainty
- The activity is measured in Activity in the reverse reaction in Hernandez (2006) et. al.
is sampled based on Haldane equation
using the value
,
and
.
Alternative-1 the reported fixed point value can be considered with the standard deviation calculated based on the same ratio of which is
. This gives the value
Alternative-2 Calculating from
based on Haldane equation which gives the value of 2.911 and with the same percent of erro Std. Dev. is 0.90.
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
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Sampled based on the Haldane equation. Alternative: ![]() ![]() |
![]() ![]() |
||
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mM | Human liver | |
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mM | Human liver | |
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mM | ![]() |
Equilibrium constant
Equilibrium constant | Conditions | Source |
---|---|---|
0.045 | pH=8, T=25°C | Bergmeyer Methods of enzymatic analysis page 515[4] |
0.041 | pH=7, T=25°C | Voet et al.[5] from Newshole et al. (1973) [6]p 97:
|
0.048 | pH=7, T=25°C | Lehninger, (1975)[7] p 408:
|
0.0475 | pH=7, T=25°C | Lehninger, (1975)[7] p 396. |
- Taking average of all those values give
References
- ↑ 1.0 1.1 1.2 1.3 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
<ref>
tag; name "Hernandez2011" defined multiple times with different content - ↑ 2.0 2.1 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)
- ↑ 3.0 3.1 3.2 Snyder, R.; Lee, E.W. (1975), Triosephosphate isomerase from human and horse liver,Methods Enzymol. 41B, 430-434
- ↑ Bergmeyer H.U. (1974) Methods of enzymatic analysis, Publisher: Verlag Chemie (vol 1)
- ↑ 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
- ↑ 7.0 7.1 Lehninger, A.L. (1975) Biochemistry (2nd edn), Worth