Data items in the ENTITY_NAME_COM category record the common name
               or names associated with the entity. In some cases, the entity
               name may not be the same as the name of the biological structure.
               For instance, hemoglobin alpha chain would be the entity common
               name, not hemoglobin.
 
     loop_
    _entity_name_com.entity_id
    _entity_name_com.name
     1  'HIV-1 protease monomer'
     1  'HIV-1 PR monomer'
     2  'acetyl-pepstatin'
     2  'acetyl-Ile-Val-Asp-Statine-Ala-Ile-Statine'
     3  'water'