This term is mapped to MGED. Do not obsolete without consulting MGED ontology. The term 'protein' was merged with 'polypeptide'. Although 'protein' was a sequence_attribute and therefore meant to describe the quality rather than an actual feature, it was being used erroneously. It is replaced by 'peptidyl' as the polymer attribute.

A sequence of amino acids linked by peptide bonds which may lack appreciable tertiary structure and may not be liable to irreversible denaturation.