\frac{dx_{1}}{dt} = k_{3} / \left(k_{11} + x_{2}\right) - k_{8} \cdot x_{1}\\ \frac{dx_{2}}{dt} = k_{1} \cdot \left(\left(k_{4} + k_{5} \cdot x_{1}\right) \cdot x_{2} \cdot x_{3} / \left(k_{12} + x_{1}^{2}\right) - k_{9} \cdot x_{2}\right)\\ \frac{dx_{3}}{dt} = k_{1} \cdot k_{2} \cdot \left(k_{6} \cdot x_{1} - \left(k_{10} \cdot x_{3} + k_{7} \cdot x_{1} \cdot x_{3} / \left(k_{13} + x_{1}\right)\right)\right)