Difference between revisions of "Adenylate kinase"

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[[Category:No Uncertainty]]
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Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides.
 
Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides.
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! Value
 
! Value
 
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| k<sub>1</sub>=442, k<sub>2</sub>=1000
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| <math>K_1=1 \pm 0.04</math>, <math>K_2=2.26 \pm 0.09044</math>
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| The kinetic parameters of adenylate kinase are unknown. Therefore, it was modeled using mass action kinetics with parameters k1 and k2 consistent with the equilibrium constant of the reaction. The equilibrium constant (Keq=0.442) is from Bergmeyer H.U. (1974) page 486<ref name="bergmeyer74">Bergmeyer H.U. (1974) ''Methods of enzymatic analysis'', Publisher: Verlag Chemie (vol 1)</ref>:  
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| The Adenylate kinase was modeled using mass action kinetics with parameters <math>K_1</math> and <math>K_2</math> consistent with the equilibrium constant of the reaction. The equilibrium constant (Keq=2.26) is from Bergmeyer H.U. (1974) page 486<ref name="bergmeyer74">Bergmeyer H.U. (1974) ''Methods of enzymatic analysis'', Publisher: Verlag Chemie (vol 1)</ref>:  
 
<math>Keq(ATP+AMP  \rightarrow 2*ADP, pH=7.4, T=25^oC)=2.26</math><br/>
 
<math>Keq(ATP+AMP  \rightarrow 2*ADP, pH=7.4, T=25^oC)=2.26</math><br/>
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<math>\Rightarrow Keq(2*ADP  \rightarrow ATP+AMP, pH=7.4, T=25^oC)= \frac{1}{2.26}=0.442</math>.
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In Mass action rate law the relationship is <math>\frac{K_2}{K_1} = K_{eq}</math>. Considering <math>K_{eq} = 2.26</math> we have <math>K_2=2.26</math> and <math>K_1 = 1</math> to be consistent with the equation. The value of <math>K_1</math> and <math>K_2</math> would be varied based on the uncertainty on <math>K_{eq}</math> value mentioned in the following table. The percentage of error in Keq is <math>\approx 4</math>. With similar percent of error the value for <math>K_1 = 1 \pm 0.04</math> and <math>K_2 = 2.26 \pm 0.09044</math>
 
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== Equilibrium constant ==
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=== Equilibrium constant ===
 
{|class="wikitable"
 
{|class="wikitable"
 
! Equilibrium constant
 
! Equilibrium constant
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| 0.48+/-0.015 (mean+/-SEM; n=7)
 
| 0.48+/-0.015 (mean+/-SEM; n=7)
 
| pH=7, T=25°C, 10mM Mg2+
 
| pH=7, T=25°C, 10mM Mg2+
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| NIST database "Thermodynamics of Enzyme-Catalyzed Reactions" entry [[http://xpdb.nist.gov/enzyme_thermodynamics/enzyme_data1.pl?T1=61ATK/BUR_640 61ATK/BUR_640]] from Atkinson et al. (1961) <ref name="atkinson61">Atkinson, M. R., Burton, R. M. and Morton, R. K. (1961) Biochem J. 78(4):813–820. ([http://www.ncbi.nlm.nih.gov/pubmed/13684980 pmid: 13684980])</ref> Table 2:<br/>
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| NIST database "Thermodynamics of Enzyme-Catalyzed Reactions" entry [[http://xpdb.nist.gov/enzyme_thermodynamics/enzyme_data1.pl?T1=61ATK/BUR_640 61ATK/BUR_640]] from Atkinson et al. (1961) <ref name="atkinson61">Atkinson, M. R., Burton, R. M. and Morton, R. K. (1961) Biochem J. 78(4):813–820. ([http://www.ncbi.nlm.nih.gov/pubmed/13684980 pmid: 13684980])</ref> Table 2<br/>
 
Therefore, Keq(forward) = 0.48 +/-0.015 (n=7; mean+/-SEM calculated from individual measurements).
 
Therefore, Keq(forward) = 0.48 +/-0.015 (n=7; mean+/-SEM calculated from individual measurements).
 
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Latest revision as of 16:38, 28 May 2014


Adenylate kinase is a phosphotransferase enzyme that catalyzes the interconversion of adenine nucleotides.

Chemical equation

ATP + AMP \rightleftharpoons 2ADP

Rate equation

Reversible mass action rate law is used

K_{1}[ATP][AMP] - K_{2}[ADP]^2

Parameter values

Parameter Value Organism Remarks
K_{1} 1 [1] HeLa cell line
K_{2} 2.26 [1]

Parameters with uncertainty

Parameter Value
K_1=1 \pm 0.04, K_2=2.26 \pm 0.09044 The Adenylate kinase was modeled using mass action kinetics with parameters K_1 and K_2 consistent with the equilibrium constant of the reaction. The equilibrium constant (Keq=2.26) is from Bergmeyer H.U. (1974) page 486[2]:

Keq(ATP+AMP \rightarrow 2*ADP, pH=7.4, T=25^oC)=2.26
In Mass action rate law the relationship is \frac{K_2}{K_1} = K_{eq}. Considering K_{eq} = 2.26 we have K_2=2.26 and K_1 = 1 to be consistent with the equation. The value of K_1 and K_2 would be varied based on the uncertainty on K_{eq} value mentioned in the following table. The percentage of error in Keq is \approx 4. With similar percent of error the value for K_1 = 1 \pm 0.04 and K_2 = 2.26 \pm 0.09044

Equilibrium constant

Equilibrium constant Conditions Source
0.48+/-0.015 (mean+/-SEM; n=7) pH=7, T=25°C, 10mM Mg2+ NIST database "Thermodynamics of Enzyme-Catalyzed Reactions" entry [61ATK/BUR_640] from Atkinson et al. (1961) [3] Table 2

Therefore, Keq(forward) = 0.48 +/-0.015 (n=7; mean+/-SEM calculated from individual measurements).

References

  1. ↑ 1.0 1.1 Marín-Hernández A, Gallardo-Pérez JC, Rodríguez-Enríquez S et al (2011) Modeling cancer glycolysis. Biochim Biophys Acta 1807:755–767 (doi)
  2. ↑ Bergmeyer H.U. (1974) Methods of enzymatic analysis, Publisher: Verlag Chemie (vol 1)
  3. ↑ Atkinson, M. R., Burton, R. M. and Morton, R. K. (1961) Biochem J. 78(4):813–820. (pmid: 13684980)
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