Difference between revisions of "Team:BIT-China/H2O2DecompositionModel"

$$\frac{\mathrm{d_{\mathit{p}_{e}}} }{\mathrm{d} t}=k_{1}(p_{i}-p_{e})v$$

$$\frac{\mathrm{d_{\mathit{p}_{i}}} }{\mathrm{d}t}=k_{1}(p_{e}-p_{i})-(k_{2}+k_{3}\frac{g}{k_{g}+g})p_{i}$$

$$\frac{\mathrm{d_{\mathit{g}}} }{\mathrm{d} t}=-k_{3}(\frac{g}{k_{g}+g})p_{i}$$

The ODE model accounted for intracellular and extracellular H₂O₂ levels, and the consumption of a finite antioxidant capacity using three rates:

• 1) The membrane permeability (k1).^[2][3][4]
• 2) Intracellular slow degradation rate (k2).^[5]
• 3) Intracellular fast degradation rate (k3) dependent upon a finite capacity (g), e.g. NADPH levels in naive cells.^[6]

We reviewed the above literature and combined the results of the wet experiment, as shown in Fig.3, to determine the parameters required for the model simulation, listed in the table below.

Table 1. Description of Variables Used in The Kinetic Model.

We used MATLAB to simulate the kinetics of extracellular and intracellular H₂O₂ changes over time. (Fig. 2)

To verify the feasibility of the model and to confirm this dynamic process, we did some experiments using our system's output, roGFP2-Orp1. The results show that the fluorescence ratio value I405/I488, an oxidant condition indicator, decreased by time when S. cerevisiae exposed to different concentrations of H₂O₂. This ratio's decreasing stands for the increasing of intercellular H₂O₂ concentration. It also stopped at a stable concentration at last, which's correspond to our model's result.

In this model, we successfully simulated the kinetics of extracellular and intracellular H₂O₂ changes over time. Furthermore, the dynamic process of fluorescence ratio value by time was detected by using roGFP2-Orp1 green fluorescent protein in wet experiment, and the feasibility of the model was further verified.