A Protein Group is a collection of proteins identified by a set of peptides. More in details, a Protein Group:

• is represented by a master (or typical) protein
• contains a collection of peptides identifying this master protein
• contains a collection of proteins having the sameset of peptides
• contains a collection of proteins having a subset of peptides

A Protein Group is quite similar to a Mascot protein hit, but operates at the Context level.

Protein groups are obtained when running the Protein Grouping algorithm on a given context.