Protein IB5
The protein IB5 is a human parotid salivary protein containing several repeats of a short proline-rich sequence (hence the name of proline rich proteins or PRP for this class of proteins) and known to bind with polyphenols (binding responsible for the astringency mouth feel).
References
- Tannin interactions with a full-length human salivary proline-rich protein display a stronger affinity than with single proline-rich repeats, Adrian J. Charlton, Nicola J. Baxtera Terence H. Lilley, Edwin Haslam, Charles J. McDonald and Michael P. Williamson, FEBS Letters, Volume 382, Issue 3, 18 March 1996, Pages 289-292, doi:10.1016/0014-5793(96)00186-X