A peptide with a ProGln C terminus in the human saliva peptidome exerts bactericidal activity against Propionibacterium acnes.

Nine proline-rich peptides ending with a proline-glutamine C terminus in a salivary peptidome were sequenced by matrix-assisted laser desorption ionization time of flight time of flight tandem mass spectrometry. A GPPPQGGRPQ peptide binds gram-positive Propionibacterium acnes and considerably inhibits bacterial growth. The peptide exhibiting innate immunity may be applied for treatment of various P. acnes-associated human diseases.