Table 2. Protein interaction data sets.

Data set name	Species	Nodes		Links		Source
		Total	LCC	Total	LCC
Online Predicted Human Interaction Database (OPHID)	H. sapiens	8,199	7,984	37,968	37,900	Brown & Jurisica [41](curated by Taylor et al. [2])
Filtered yeast interactome (FYI)	S. cerevisiae	1379	778	2493	1798	Han et al. [1]
Filtered high-confidence (FHC)	S. cerevisiae	2559	2233	5991	5750	Bertin et al. [4]
Database of Interacting Proteins core (DIPc)	S. cerevisiae	2808	2587	6212	6094	http://dip.doe-mbi.ucla.edu/(October 2007 version)
Center for Cancer Systems Biology Human Interactome version 1 (CCSB-HI1)	H. sapiens	1,549	1,307	2,611	2,483	Rual et al. [49]
Protein-fragment complementation assay (PCA)	S. cerevisiae	1124	889	2770	2407	Tarassov et al. [47]

The protein interaction data sets that we used in this paper. LCC refers to the largest connected component.