PubChem provides information on the biological activities of small molecules. PubChem is organized as three linked databases - PubChem Substance, PubChem Compound, and PubChem BioAssay. PubChem also provides a fast chemical structure similarity search tool.
The Taxonomy Database is a curated classification and nomenclature for all of the organisms in the public sequence databases. This currently represents about 10% of the described species of life on the planet. If you are looking for a sequence from a particular species, finding the record in Taxonomy will link to the relevant sequences in the Nucleotide, Protein, and Gene databases.
Contains sequence and map data from the whole genomes of over 1000 species or strains spanning bacteria, archaea, eukaryota, viruses, phages, plasmids, and organelles. The genomes represent both completely sequenced genomes and those with sequencing in-progress.
Contains amino acid sequences created from translating coding regions described in nucleotide records in multiple databases, including GenBank, EMBL, and DDBJ, as well as protein-specific resources including UniProt, Protein Research Foundation (PRF), and the Protein Data Bank (PDB).