PRotein Ontology (PRO) Release 15.0 (21-Jan-2011)

There are 26167 PRO terms
   304 terms are in the 'family' category.
  18205 terms are in the 'gene' category.
  1235 terms are in the 'sequence' category.
  5705 terms are in the 'modification' category.
   35 terms are in the 'complex' category.
   178 terms are in the 'organism-gene' category.
   225 terms are in the 'organism-sequence' category.
   120 terms are in the 'organism-modification' category.
   49 terms are in the 'organism-complex' category.
    8 terms are in the 'union' category.
1515 terms have some kind of annotation, codifying the information from 976 papers.
  2133 connections to GO (744 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.