Bio4j is a bioinformatics graph based DB including most data available in UniProt KB (SwissProt + Trembl), Gene Ontology (GO), UniRef (50,90,100), RefSeq, NCBI taxonomy, and Expasy Enzyme DB. (Manuscript in preparation)

Check this presentation at slideshare for a general overview of the project.

Bio4j is 100% open source and it’s released under AGPLv3 license.