Prosite
Prosite is an online database of protein families and domains, created by Amos Bairoch, which can be used to analyse protein function of a known amino acid sequence.
Prosite allows you to search using a particular sequence for protein motifs against those stored in the database. These motifs may include; post-translational modifications, domains,
DNA or RNA associated proteins, enzymes, oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, electron transport proteins, other transport proteins, structural proteins, receptors, cytokines and growth factors, hormones and active peptides, toxins, inhibitors, protein secretion and chaperones.
A search provides background information on structure and function of the protein which can then be used alongside other tools such as BLAST, SMART and Pfam for any additonal information from the amino acid sequence to help determine the function of an uncharacterised protein [1].
Prosite can be accesed via http://www.ebi.ac.uk/Tools/ppsearch/