PRotein Ontology (PRO) Release 17.0 (29-Mar-2011)

There are 26677 PRO terms
   304 terms are in the 'family' category.
  18200 terms are in the 'gene' category.
  1298 terms are in the 'sequence' category.
  5871 terms are in the 'modification' category.
   43 terms are in the 'complex' category.
   285 terms are in the 'organism-gene' category.
   305 terms are in the 'organism-sequence' category.
   163 terms are in the 'organism-modification' category.
   88 terms are in the 'organism-complex' category.
    8 terms are in the 'union' category.
1544 terms have some kind of annotation, codifying the information from 1031 papers.
  2280 connections to GO (773 PRO terms).
   374 connections to MOD (327 PRO terms).
   604 connections to Pfam (362 PRO terms).
   338 connections to SO (317 PRO terms).
   306 annotations of a phenotype (299 PRO terms).

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