I think it is better to convert your model to excel file. After that you import the model to your code.

Yess.. That is what i am doing... M adding reactions in excel only.. But after adding those reactions the flux values that i am getting are unrealistic...

May be is related to co-factors such as ATP or NAD+, if your reaction contains them. So try to make your the reaction is an irreversible.

The reason for this likely is an unstable matrix, i.e. the condition number of your Stoichiometric matrix is too high and it produces large errors when inverted to calculate the unknown fluxes. Co-factors are not added as metabolites for MFA (because you are considering only a sub-system of the whole metabolic network), so that would not give you resolution of your problem.

Hi,

I have little experience about your problem.

I assume you are using a SBML model. If so, Antimony could help you in editing the existing file.

While editing huge models be cautious about declaration of new metabolites, their boundaries and limits.

As others pointed out, this NAD and NADH is a problem if you edit your model in matrix level.

Try using FAME. You can add new reactions online if your genome scale model is well known like Reed’s E. coli.

Good luck!