From BITS wiki
Interaction databases gather evidence of physical interactions between protein and/or nucleic acids.
- IntAct - database system and analysis tools for molecular interaction data (EBI)
- MIM - networks of multi-protein complexes, protein modifications, and enzymes that are substrates of other enzymes.
- PEIMAP - Experimental interaction database, including functional and physicochemical annotations and providing predicted PPIs.
- INstruct - database of high-quality protein interactome networks
- PsicQuic - Meta-search different databases.