Table 1.
Integration of protein–protein interaction data
| Database | Version | Proteins | Interactions | Independent reports |
|---|---|---|---|---|
| HPRD (33) | 1 September 2007 | 8697 | 34 938 | 17 770 |
| BioGRID (34) | 1 February 2009 | 7163 | 23 588 | 8815 |
| IntAct (35) | 23 January 2009 | 7066 | 22 119 | 1374 |
| MINT (36) | 5 February 2009 | 5151 | 12 653 | 1210 |
| DIP (37) | 26 January 2009 | 1108 | 1326 | 739 |
| NCG | 21 June 2009 | 11 988 | 68 498 | 19 886 |
Data from five different sources are integrated in NCG. To derive a non-redundant version of the network, proteins are counted as number of non-redundant Entrez IDs. The number of interactions refers to non-redundant primary interactions; the independent reports refer to the number of published papers that define the interactions.