PRotein Ontology (PRO) Release 9.0 (05-Mar-2010)

There are 24794 PRO terms
  5363 terms are in the 'modification' category.
  965 terms are in the 'sequence' category.
  18159 terms are in the 'gene' category.
  270 terms are in the 'family' category.
1257 terms have some kind of annotation, codifying the information from 890 papers.
 1869 connections to GO (623 PRO terms).
 236 connections to MOD (195 PRO terms).
 599 connections to Pfam (358 PRO terms).
 325 connections to SO (307 PRO terms).
 296 annotations of a phenotype (289 PRO terms).

The ontology includes a subset of terms from other ontologies and resources that are used for logical definitions.

_Changes from Release 8.0_

We have added a new node for proteolytic cleavage products, which are derived_from proteins. This node will facilitate the creation of
logical definitions. As a result, we have created a new root node for both, "amino acid chain." This new root node will also allow the future inclusion of peptides created de novo (non-ribosomally).

We have added terms based on the Escherichia coli proteome.