CAT and cancer: The reaction network, representing both apoptotic pathways in the extracellular compartment of a cancer cell, and their interaction with catalase, consists of the following reactions:(1)2O2•−+2H+k1→SODH2O2+O2,(2) •NO+O2•−k2⇌k−2ONOO−,(3)2H2O2k3→CATO2+2H2O,(4)2ONOO−k4→CATO2+2NO2−,(5)H2O2+Cl−+H+k5→PODHOCl+H2O,(6)HOCl+O2•−k6⇌k−6 •OH+Cl−+O2,(7)ONOO−+H+k7⇌k−7ONOOH,(8)ONOOHk8⇌k−8 •NO2+ •OH,where ki is the rate constant of the forward reaction for reaction (i) and k−i is the rate constant for the backward reaction.