Reaction16 showed in the paper is a fast equilibrium reaction. HO2* =" H+" + "O2*-". So in the equation (1) in the paper, you will see there is one item k10*"HO2*" . However, most simulation software does not support fast reaction yet, so curator creat this fake v16 reaction in order to make the final ODE correct.
This model is according to the paper from Axel Kowald Alternative pathways as mechanism for the negative effects associated with overexpression of superoxide dismutase. Reactions from 1 to 17 are listed in the paper, note that for clarity species whose concentrations are assumed to be constant (e.g.water, oxygen,protons, metal ions) are omitted from the diagram. In the paper, v16 is a fast reaction, but we do not use fast reaction in the model. Figure2 has been reproduced by both SBMLodeSolver and Copasi4.0.20(development) . Figure 3 has been obtained with Copasi4.0.20(development) using parameter scan. The steady-state of [LOO*] a little bit lower than showed on the paper, I guess it may be the simulation method used in the paper use fast reaction and also the reaction (5) listed on Page 831 on the paper is slightly different from equation (2) on Page 832. The rest of them are the quite the same. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not. To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.