Difference between revisions of "Enolase"

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|mM
 
|mM
 
|Human muscle
 
|Human muscle
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=== Equilibrium constant ===
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{|class="wikitable"
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! Equilibrium constant
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! Conditions
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! Source
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|-
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| 3.6
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| pH=7, T=25°C
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| 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>p 97:<br/>
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<math>\Delta G' = -3.2\ kJ.mol^{-1}</math>, <math>Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{3200}{8.31*298.15}) \approx 3.6</math>
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|-
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| 6.7
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| T=25°C
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| Bergmeyer ''Methods of enzymatic analysis'' page 449<ref name="bermeyer74">Bergmeyer H.U. (1974) ''Methods of enzymatic analysis'', Publisher: Verlag Chemie (vol 1)</ref>
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|-
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| 2.03
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| pH=7, T=297.15 K
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| From Meyerhof et al. (1947)<ref name="meyerhof49">Meyerhof O. and Oesper P. (1947) J. Biol. Chem. 170(1):1-22 [[http://www.jbc.org/content/170/1.toc J. Biol. Chem.]]</ref>:
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<math>\Delta G' = -1.757\ kJ.mol^{-1}</math>, <math>Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{1757}{8.31*298.15}) \approx 2.03</math>
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|-
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| 4.29
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| pH=7, T=298.15 K, c(MgSO4,mol dm-3) =0.001
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| From Wold et al. (1957) (NIST database<ref name="nist">Goldberg R.N., Tewari Y.B. and Bhat T.N. (2004) Bioinformatics 20(16):2874-2877 [[http://www.ncbi.nlm.nih.gov/pubmed?term=15145806 pmid: 15145806]]</ref> [[http://xpdb.nist.gov/enzyme_thermodynamics/enzyme_data1.pl?T1=57WOL/BAL_1173 57WOL/BAL_1173]])
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|-
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| 3.92
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| pH=7, T=298.15 K, c(MgSO4,mol dm-3) =0.01
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| From Wold et al. (1957) (NIST database<ref name="nist"></ref> [[http://xpdb.nist.gov/enzyme_thermodynamics/enzyme_data1.pl?T1=57WOL/BAL_1173 57WOL/BAL_1173]])
 
|}
 
|}
  
 
==References==
 
==References==
 
<references/>
 
<references/>

Revision as of 15:25, 24 June 2014

Enolase, also known as phosphopyruvate hydratase, catalysis the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP). This is the penultimate step of glycolysis.

Chemical equation

2PG \rightleftharpoons PEP

Rate equation

Mono-substrate reversible Michaelis-Menten equation is used. [1]

\frac{V_{mf}\frac{[2PG]}{K_{2PG}}-V_{mr}\frac{[PEP]}{K_{PEP}}}{1 + \frac{[2PG]}{K_{2PG}} + \frac{[PEP]}{K_{PEP}}}

Modified rate law to take Thermodynamic constraint into consideration

\frac{V_{mf}\frac{[2PG]}{K_{2PG}} \left( 1 -\frac{[PEP]}{K_{eq} [2PG]} \right)}{1 + \frac{[2PG]}{K_{2PG}} + \frac{[PEP]}{K_{PEP}}}

Parameter values

Parameter Value Units Organism Remarks
V_{mf} 0.34 [2] \text{mM min}^{-1} HeLa cell line
V_{mr} 0.38[1] \text{mM min}^{-1}
Km_{2PG} 0.038[1] mM
Km_{PEP} 0.06[1] mM

Parameters with uncertainty

  • Three values for Km_{2PG} is collected. The values are 0.20 [3], 0.199 [3], 0.038 [1]. The mean and std. dev. is 0.145 \pm 0.07
  • Similarly for Km_{PEP} three reported values are 0.58, 0.702, 0.06. The uncertainty is then 0.44 \pm 0.276.
  • In Pietkiewicz et. al. (2009) [3] V_{mr} is reported as 1.4 mmol/min^{-1} and Marín-Hernández et. al. (2011) [1] reported it to be 0.4. The mean and the std. dev. calculated from these two values are 0.9 \pm 0.5.
Parameter Value Units Organism Remarks
V_{mf} 0.36 \pm 0.15 (5) [2] \text{mM min}^{-1} HeLa cell line
V_{mr} 0.9 \pm 0.5 \text{mM min}^{-1}
Km_{2PG} 0.145 \pm 0.07 mM Human muscle
Km_{PEP} 0.44 \pm 0.276 mM Human muscle

Equilibrium constant

Equilibrium constant Conditions Source
3.6 pH=7, T=25°C Voet et al.[4] from Newshole et al. (1973) [5]p 97:

\Delta G' = -3.2\ kJ.mol^{-1}, Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{3200}{8.31*298.15}) \approx 3.6

6.7 T=25°C Bergmeyer Methods of enzymatic analysis page 449[6]
2.03 pH=7, T=297.15 K From Meyerhof et al. (1947)[7]:

\Delta G' = -1.757\ kJ.mol^{-1}, Keq = exp(-\frac{\Delta G'}{RT}) = exp(\frac{1757}{8.31*298.15}) \approx 2.03

4.29 pH=7, T=298.15 K, c(MgSO4,mol dm-3) =0.001 From Wold et al. (1957) (NIST database[8] [57WOL/BAL_1173])
3.92 pH=7, T=298.15 K, c(MgSO4,mol dm-3) =0.01 From Wold et al. (1957) (NIST database[8] [57WOL/BAL_1173])

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 (doi)
  2. ↑ 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. ↑ 3.0 3.1 3.2 Pietkiewicz, J., Gamian, A., Staniszewska, M., & Danielewicz, R. (2009), Inhibition of human muscle-specific enolase by methylglyoxal and irreversible formation of advanced glycation end products, Journal of Enzyme Inhibition and Medicinal Chemistry, 24, 356–364
  4. ↑ Voet, D., Voet., J.G. and Pratt, C. W. (1999) Fundamentals of biochemistry, Wiley
  5. ↑ Newshole, E.A. and Stuart, C. (1973) Regulation in Metabolism, Wiley
  6. ↑ Bergmeyer H.U. (1974) Methods of enzymatic analysis, Publisher: Verlag Chemie (vol 1)
  7. ↑ Meyerhof O. and Oesper P. (1947) J. Biol. Chem. 170(1):1-22 [J. Biol. Chem.]
  8. ↑ 8.0 8.1 Goldberg R.N., Tewari Y.B. and Bhat T.N. (2004) Bioinformatics 20(16):2874-2877 [pmid: 15145806]
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