I am building a model in SimBiology where I want to model the production gas vesicle proteins and subsequent formation of gas vesicles. Ideally, I want to model this such that there is a boundary condition where an X amount of gas vesicle proteins (or above the essential concentration) will lead to an assembly reaction.
I tried this by adding the chemical reaction: X [Gas vesicle protein] -> [Gas vesicle]
However, this leads to a negative values for the gas vesicle species. Is there a way in which I can set a condition for this reaction to occur (for example require that enough gas vesicle proteins are present in order for the reaction to be active)? Or could there maybe be a better way to solve this?
The model I'm building is a stiff model, and I am using the sundials solver.
Thank you in advance!