All computation was performed on Mac OS × 10.6.8, 1.86 GHz Inter Core 2 Duo Processor, 2 GB 1067 MHz DDR3 Memory. COBRA toolbox v2.0.5 was added to the path of MATLAB_R2012b, including SBML Toolbox_4.1.0 bundled in the package. libSBML_5.7.0 was installed to access the Systems Biology Makeup Language. Gurobi_5.1.0 was used as the LP solver.