\frac{dx_{1}}{dt} = \left(1 \cdot k_{17} \cdot k_{18} \cdot k_{19} \cdot x_{2} \cdot k_{2} \cdot x_{1} / \left(k_{3} + x_{1}\right) / \left(k_{2} \cdot x_{1} / \left(k_{3} + x_{1}\right) \cdot k_{19} + k_{5} / \left(k_{6} + x_{1}\right)\right)^{4} + -1 \cdot k_{17} \cdot k_{20} \cdot x_{1}^{2} / \left(k_{21}^{2} + x_{1}^{2}\right) + 1 \cdot k_{17} \cdot k_{22} + 1 \cdot k_{17} \cdot k_{30} \cdot \left(x_{3} - x_{1}\right)\right) / k_{17}\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{17} \cdot k_{11} / \left(k_{12} + x_{1}\right) \cdot \left(1 - x_{2}\right) + -1 \cdot k_{17} \cdot k_{2} \cdot x_{1} / \left(k_{3} + x_{1}\right) \cdot \left(k_{8} + k_{9} \cdot x_{1}\right) / \left(k_{6} + x_{1}\right) \cdot x_{2} \cdot k_{23} / \left(k_{2} \cdot x_{1} / \left(k_{3} + x_{1}\right) \cdot k_{23} + k_{5} / \left(k_{6} + x_{1}\right)\right)\right) / k_{17}\\
\frac{dx_{3}}{dt} = \left(1 \cdot k_{17} \cdot k_{24} \cdot k_{25} \cdot x_{4} \cdot k_{2} \cdot x_{3} / \left(k_{3} + x_{3}\right) / \left(k_{2} \cdot x_{3} / \left(k_{3} + x_{3}\right) \cdot k_{25} + k_{5} / \left(k_{6} + x_{3}\right)\right)^{4} + -1 \cdot k_{17} \cdot k_{26} \cdot x_{3}^{2} / \left(k_{27}^{2} + x_{3}^{2}\right) + 1 \cdot k_{17} \cdot k_{28} + -1 \cdot k_{17} \cdot k_{30} \cdot \left(x_{3} - x_{1}\right)\right) / k_{17}\\
\frac{dx_{4}}{dt} = \left(1 \cdot k_{17} \cdot k_{11} / \left(k_{12} + x_{3}\right) \cdot \left(1 - x_{4}\right) + -1 \cdot k_{17} \cdot k_{2} \cdot x_{3} / \left(k_{3} + x_{3}\right) \cdot \left(k_{8} + k_{9} \cdot x_{3}\right) / \left(k_{6} + x_{3}\right) \cdot x_{4} \cdot k_{29} / \left(k_{2} \cdot x_{3} / \left(k_{3} + x_{3}\right) \cdot k_{29} + k_{5} / \left(k_{6} + x_{3}\right)\right)\right) / k_{17}