Figure 3

Number of essential proteins identified by ION and eight other existing centrality methods. The proteins in PPI network are ranked in the descending order based on their ranking scores computed by ION, Degree Centrality (DC), Betweenness Centrality (BC), Closeness Centrality (CC), Subgraph Centrality (SC), Eigenvector Centrality (EC), Information Centrality (IC), Edge Clustering Coefficient Centrality (NC), and centrality based on edge clustering coefficient and Pearson correlation coefficient (PeC). Then, top 1%, 5%, 10%, 15%, 20% and 25% of the ranked proteins are selected as candidates for essential proteins. According to the list of known essential proteins, the number of true essential proteins is used to judge the performance of each method. The figure shows the number of true essential proteins identified by each method in each top percentage of ranked proteins. Since the total number of ranked proteins is 5093. The number of proteins ranked in top 1% is about 51(=5093*1%). The digits in brackets denote the number of proteins ranked in each top percentage.