\frac{dx_{1}}{dt} = \left(1 \cdot k_{90} \cdot k_{4} \cdot \left(k_{1} / \left(1 + k_{74} / k_{72}\right) + k_{65}\right) \cdot \left(k_{67} - x_{1} \cdot k_{90} - x_{2} \cdot k_{90}\right) / \left(k_{5} + k_{67} - x_{1} \cdot k_{90} - x_{2} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{51} + k_{6} \cdot x_{11} \cdot k_{90}\right) \cdot x_{1} \cdot k_{90} / \left(k_{7} + x_{1} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{8} + k_{12} \cdot x_{10} \cdot k_{90}\right) \cdot \left(k_{67} - x_{1} \cdot k_{90} - x_{2} \cdot k_{90}\right) / \left(k_{9} + k_{67} - x_{1} \cdot k_{90} - x_{2} \cdot k_{90}\right) \cdot k_{10} / \left(k_{10} + \left(x_{4} \cdot k_{90} + x_{5} \cdot k_{90}\right) / \left(1 + k_{76} / k_{73}\right)\right) / k_{90} + -1 \cdot k_{90} \cdot k_{11} \cdot x_{2} \cdot k_{90} / \left(k_{13} + x_{2} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{3}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{14} + k_{15} \cdot x_{6} \cdot k_{90} / \left(k_{16} + x_{6} \cdot k_{90}\right)\right) / k_{90} + -1 \cdot k_{90} \cdot k_{17} \cdot x_{3} \cdot k_{90} / k_{90}\right) / k_{90}\\
\frac{dx_{4}}{dt} = \left(1 \cdot k_{90} \cdot k_{18} \cdot x_{3} \cdot k_{90} / \left(k_{19} + x_{3} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot k_{25} \cdot x_{4} \cdot k_{90} / k_{90} + -1 \cdot k_{90} \cdot \left(k_{20} \cdot x_{1} \cdot k_{90} + k_{21} \cdot x_{9} \cdot k_{90} / \left(1 + k_{75} / k_{60}\right)\right) \cdot x_{4} \cdot k_{90} / \left(k_{22} + x_{4} \cdot k_{90}\right) / k_{90} + 1 \cdot k_{90} \cdot \left(k_{23} + k_{59} \cdot x_{11} \cdot k_{90}\right) \cdot x_{5} \cdot k_{90} / \left(k_{24} + x_{5} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{5}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{20} \cdot x_{1} \cdot k_{90} + k_{21} \cdot x_{9} \cdot k_{90} / \left(1 + k_{75} / k_{60}\right)\right) \cdot x_{4} \cdot k_{90} / \left(k_{22} + x_{4} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{23} + k_{59} \cdot x_{11} \cdot k_{90}\right) \cdot x_{5} \cdot k_{90} / \left(k_{24} + x_{5} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{6}}{dt} = \left(1 \cdot k_{90} \cdot k_{26} \cdot x_{5} \cdot k_{90} / \left(1 + k_{76} / k_{73}\right) \cdot \left(k_{68} - x_{6} \cdot k_{90} - x_{13} \cdot k_{90}\right) / \left(k_{27} + k_{68} - x_{6} \cdot k_{90} - x_{13} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{52} + k_{28} \cdot x_{11} \cdot k_{90}\right) \cdot x_{6} \cdot k_{90} / \left(k_{29} + x_{6} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{7}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{30} + k_{31} \cdot x_{6} \cdot k_{90} / \left(k_{32} + x_{6} \cdot k_{90}\right)\right) / k_{90} + -1 \cdot k_{90} \cdot k_{33} \cdot x_{7} \cdot k_{90} / k_{90}\right) / k_{90}\\
\frac{dx_{8}}{dt} = \left(1 \cdot k_{90} \cdot k_{34} \cdot x_{7} \cdot k_{90} / \left(k_{35} + x_{7} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{40} + k_{41} \cdot x_{10} \cdot k_{90}\right) \cdot x_{8} \cdot k_{90} / \left(k_{42} + x_{8} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{36} \cdot k_{2} + k_{66}\right) \cdot x_{8} \cdot k_{90} / \left(k_{37} + x_{8} \cdot k_{90}\right) / k_{90} + 1 \cdot k_{90} \cdot k_{38} \cdot x_{9} \cdot k_{90} / \left(k_{39} + x_{9} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{9}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{36} \cdot k_{2} + k_{66}\right) \cdot x_{8} \cdot k_{90} / \left(k_{37} + x_{8} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot k_{38} \cdot x_{9} \cdot k_{90} / \left(k_{39} + x_{9} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{10}}{dt} = \left(1 \cdot k_{90} \cdot k_{43} \cdot x_{1} \cdot k_{90} \cdot \left(k_{69} - x_{10} \cdot k_{90}\right) / \left(k_{44} + k_{69} - x_{10} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot \left(k_{53} + k_{45} \cdot x_{11} \cdot k_{90}\right) \cdot x_{10} \cdot k_{90} / \left(k_{46} + x_{10} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{11}}{dt} = \left(1 \cdot k_{90} \cdot k_{47} \cdot x_{1} \cdot k_{90} \cdot \left(k_{70} - x_{11} \cdot k_{90}\right) / \left(k_{48} + k_{70} - x_{11} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot k_{49} \cdot x_{11} \cdot k_{90} / \left(k_{50} + x_{11} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{12}}{dt} = \left(1 \cdot k_{90} \cdot \left(k_{54} \cdot x_{9} \cdot k_{90} / \left(1 + k_{75} / k_{61}\right) + k_{55} \cdot x_{1} \cdot k_{90}\right) \cdot \left(k_{71} - x_{12} \cdot k_{90}\right) / \left(k_{56} + k_{71} - x_{12} \cdot k_{90}\right) / k_{90} + -1 \cdot k_{90} \cdot k_{57} \cdot x_{12} \cdot k_{90} / \left(k_{58} + x_{12} \cdot k_{90}\right) / k_{90}\right) / k_{90}\\
\frac{dx_{13}}{dt} = 1 \cdot k_{90} \cdot \left(k_{62} \cdot \left(k_{68} - x_{6} \cdot k_{90} - x_{13} \cdot k_{90}\right) \cdot \left(k_{77} - x_{13} \cdot k_{90}\right) - k_{63} \cdot x_{13} \cdot k_{90}\right) / k_{90} / k_{90}