An example of the use of network thermodynamic modeling in experiments on the mechanisms of oxygen toxicity

The authors discuss the use of network thermodynamic modeling in free radical research. They have developed a network thermodynamic model to aid in experimental research on the effect of oxygen free radicals on the calcium-ATPase of vascular smooth muscle sarcoplasmic reticulum. The model was intended to test the validity of the experimental system and to estimate the concentrations of the various reactive species. The following reactions were included: xanthine oxidase generation of the superoxide radical; the various dismutation reactions; the superoxide-driven Fenton reaction for the generation of hydroxyl radicals; and the LDH-catalyzed chain oxidation of NADH. The use of the model made it possible to quickly see that the production of one reactive species (hydrogen peroxide) would not be nearly adequate enough to have any significant bearing on the experimental results. Further, the model lead to the suggestion that superoxide, and not the more reactive hydroxyl radical, was the injurious species in the system