Raf-1-Removal

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Binding Reaction

\text{Raf1} + \text{activePKA}  \rightleftharpoons \text{removedRaf1} + \text{activePKA}

Kinetic Equation


\frac{k_{cat} \cdot [\text{activePKA}] \cdot [\text{Raf1}] \cdot (1-\frac{[\text{removedRaf1}]}{[\text{Raf1}] \cdot K_{eq}})}{Km_{\text{Raf1}}\cdot(1 + \frac{[\text{Raf1}]}{Km_{\text{Raf1}}} + \frac{[\text{removedRaf1}]}{Km_{\text{removedRaf1}}})}

final Parameter

Because only a subunit was measured the standard deviation is increased by 1.5.

k_{cat} =  1.92475 \pm 0.64133 \cdot 1.5\; \frac{1}{s} =  1.92475 \pm 0.962\; \frac{1}{s}

K_{m} = 42.7 \pm 8.984 \cdot 1.5\; \mu M = 42.7 \pm 13.4761\; \mu M

Parameter

Calculation Reference

The calculation of the vmax values that have the right unity is as follows:

 1 Da = 1.66 \cdot 10^{-27} kg = 1.66 \cdot 10^{-21}\ mg

 m(C \gamma) = 41000 Da = 6.806 \cdot 10^{-17}\ mg

Failed to parse (lexing error): \text{#enzyme per mg} = \frac{1 mg}{m(C \gamma)} = 1.469 \cdot 10^{16}

Failed to parse (lexing error): n(\text{enzyme per mg}) = \frac{\text{#enzyme/mg}}{6.023\cdot 10^{17}}= 0.024395\ \mu mol

 v_{max}(1/min) = v_{max}(\frac{\mu mol}{min\cdot n(\text{enzyme})})

 v_{max}(1/s)=\frac{v_{max}(1/min)}{60}

 m(C \alpha) = 42000 Da = 6.972 \cdot 10^{-17}\ mg

Failed to parse (lexing error): \text{#enzyme per mg} = \frac{1 mg}{m(C \gamma)} = 1.4343 \cdot 10^{16}

Failed to parse (lexing error): n(\text{enzyme per mg}) = \frac{\text{#enzyme/mg}}{6.023\cdot 10^{17}}= 0.023813\ \mu mol

 v_{max}(1/min) = v_{max}(\frac{\mu mol}{min\cdot n(\text{enzyme})})

 v_{max}(1/s)=\frac{v_{max}(1/min)}{60}

This calculation results in:

 v_{max}(\text{Kemptide}) = 4.829 \pm 1.120\ s^{-1}

 v_{max}(\text{Histone}) = 2.1 \pm 0.84\ s^{-1}

 v_{max}(\text{Kemptide}) = 0.20 \pm 0.07\ s^{-1}

 v_{max}(\text{Histone}) = 0.57 \pm 0.20\ s^{-1}


 k_{cat}\text{(average}) =  \frac{4.829 + 2.1 + 0.20 + 0.57}{4}\; \frac{1}{s} = 1.92475\; \frac{1}{s}

 \sigma_{k_{cat}(\text{average})} =  \frac{\frac{1.120}{4.829} + \frac{0.84}{2.1} + \frac{0.07}{0.20} + \frac{0.20}{0.57}}{4} \cdot  1.92475 \frac{1}{s} = 0.64133\; \frac{1}{s}

Zhang W. et al.(2004)[1]

KmP value and equilibrium constant

The Km value for the product is assumed to be similar but slightly higher than the the Km value of the substrate because of the similarity of the both species. Therefore the Km value of the substrate is multiplied by 1.05 to gain the one of the product and the uncertainty is increased by increasing the error on Kmsubstrate by 50%.

For information about the equilibrium constant please see here.

References

  1. Zhang W., Morris G.Z., and Beebe S.J.(2004) "Characterization of the cAMP-dependent protein kinase catalytic subunit Cgamma expressed and purified from sf9 cells." Protein Expr Purif 35.1:156-169. DOI:10.1016/j.pep.2004.01.006. (pmid:15039070)