Defining a reaction as a fraction of another reaction's rate

[Joshua Kaste]

Hello,

I am wondering if it is possible in COPASI to define a reaction's rate law such that it is always proportional to another reaction rate. I am building a model where I would like an export reaction to proceed according to regular Michaelis-Menten kinetics, but would also like an import reaction for a different species to have its rate defined as some fraction of that first export reaction's rate.

Any guidance would be greatly appreciated.

Best regards,

Joshua Kaste

[Frank Bergmann]

Hello, 

what you can do is to create a global parameter with an assignment under "Global Quantity". The Assignment would be the other reactions flux, multiplied with what fraction you want to use. Then you could choose mass action for your second reactions kinetic, and map the Parameter k1 to the global parameter created. 

Please let me know if you need more information. 

best

Frank