PRotein Ontology (PRO) Release 8.0 (14-Jan-2010)

There are 18214 PRO terms
  1093 terms are in the 'modification' category.
  941 terms are in the 'sequence' category.
  15903 terms are in the 'gene' category.
  260 terms are in the 'family' category.
1233 terms are annotated, codifying the information from 842 papers.
 1781 connections to GO (599 PRO terms).
 235 connections to MOD (194 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.