Figure 2.

Example model of insulin receptor activation. (A) Graph (kinetic scheme) G. (B) All spanning trees of graph G rooted at each vertex. (C) The corresponding Kirchhoff polynomial. (D) The graph obtained by rooting G at $v_{\text{RLp}}$. (E) The edge-deleted graph, $G⧹v_{\text{RL}}{v}_{\text{R}}$. (F) The edge-contracted graph, $G\text{/}{v}_{\text{RL}}{v}_{\text{R}}$. Labels on vertices denote names of species represented by them and W denotes a vertex obtained after the application of graph operations. Gray vertices are roots of the corresponding spanning tree and of all spanning trees when rooting a graph, respectively.