Table 2. Statistics of gold standard protein complexes.

Network	Reference database	# complexes	# proteins	# proteins in 2 complexes
Total	MIPS	220	1095	300
	SGD	324	1340	293
Gavin	MIPS	94	537	142
	SGD	118	542	136
Krogan	MIPS	119	601	193
	SGD	168	790	197
Collins	MIPS	64	437	91
	SGD	81	426	116
BioGRID	MIPS	157	1010	279
	SGD	242	1217	262

Here denotes the statistics of the total complexes of each reference database which are not mapped into PPI networks and filtered by size.