\frac{dx_{1}}{dt} = 0\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{2} \cdot k_{3} \cdot x_{3} / \left(k_{4} \cdot \left(1 + x_{2} / k_{5}\right) + x_{3}\right) + -1 \cdot k_{2} \cdot \left(k_{13} / \left(1 + k_{21} / k_{11}\right) \cdot x_{2} / \left(k_{16} \cdot \left(1 + x_{3} / k_{11}\right) + x_{2}\right) + k_{14} / \left(1 + k_{21} / k_{12}\right) \cdot x_{2} / \left(k_{15} \cdot \left(1 + x_{3} / k_{12}\right) + x_{2}\right)\right) + -1 \cdot k_{2} \cdot k_{19} \cdot x_{2} / \left(k_{20} + x_{2}\right)\right) / k_{2}\\
\frac{dx_{3}}{dt} = \left(-1 \cdot k_{2} \cdot k_{3} \cdot x_{3} / \left(k_{4} \cdot \left(1 + x_{2} / k_{5}\right) + x_{3}\right) + 1 \cdot k_{1} \cdot \left(k_{21} / \left(k_{6} + k_{21}\right) \cdot k_{7} / \left(1 + x_{2} / k_{10} + x_{3} / k_{6}\right) + k_{21} / \left(k_{8} + k_{21}\right) \cdot k_{9} / \left(1 + x_{2} / k_{10} + x_{3} / k_{8}\right)\right) + -1 \cdot k_{2} \cdot k_{17} \cdot x_{3} / \left(k_{18} + x_{3}\right)\right) / k_{2}