Figure 5
![Figure 5](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1752-0509-4-S2-S9/MediaObjects/12918_2010_Article_539_Fig5_HTML.jpg)
Model 2: cascade reaction The molecular cascade reaction of four molecules is schematically shown (A). According to the kinetics in the model (see details in Methods), a reference curve of one variable, x1, was generated for 0≦t≦1 with intervals of 0.01, under the following conditions: x1(0) = 10.0, x2(0) = 130.0, x3(0) =80.0, x4(0)=170.0, k21=5.0, k31=7.0, k41=11.0, k p 2 = 3.0, k p 3=4.0, k p 4=10.0, k e 1=5.0 and k e 2=3.0 (B).