GFSST is a robust retrieval tool for genes and gene products 
based on heir associated GO terms. Searching with GO terms
allows more flexibility than searching with a source protein.
Users can design their search by using one or multiple GO terms. 

For example, given the following terms in the Molecular Function Ontology,
search genes by funtional similarlity:

GO:0004186 carboxypeptidase C activity
GO:0005478 intracellular transporter activity
GO:0008047 enzyme activator activity
GO:0016787 hydrolase activity

Try this example. Copy the following GO IDs and paste into the Molecular 
Function GO IDs box. Then click the "Submit Query" Button.

0004186 0005478 0008047 0016787