The model was encoded and simulated using Copasi 4.15. The red and blue graphs indicate the time course of Zub and the R1Bubd, respectively. The difference between the solid and dashed curves are the initial conditions of the model. 

Solid line: Bmi1ubd=1.08, Bmi1=1.1, R1Bubd=0.12, R1B=0.1, Z=0.2, Zub=0.12, R1Buba=0.44, R1Bub=0.02 

Dashed line: Bmi1ubd=2.45, Bmi1=0, R1Bubd=0.05, R1B=0.9, Z=0, Zub=0.05, R1Buba=0, R1Bub=0 

There was an error in the rate equations provided in the supplementary for reaction 5, where the product is R1Bubd instead of Z.