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Tannin interactions with a full‐length human salivary proline‐rich protein display a stronger affinity than with single proline‐rich repeats
Author(s) -
Charlton Adrian J.,
Baxter Nicola J.,
Lilley Terence H.,
Haslam Edwin,
McDonald Charles J.,
Williamson Michael P.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00186-x
Subject(s) - proline , dissociation constant , chemistry , intramolecular force , saliva , tannin , proanthocyanidin , polyphenol , biochemistry , stereochemistry , amino acid , food science , receptor , antioxidant
The protein IB5 has been purified from human parotid saliva. This protein contains several repeats of a short proline‐rich sequence. Dissociation constants have been measured at several discrete binding sites using 1 H‐NMR for the hydrolysable tannins (polyphenols) ( , and and the condensed proanthocyanidin (−)‐epicatechin. The dissociation constants for trigalloyl glucose and pentagalloyl glucose were 15 × 10 −5 and 1.7 × 10 −5 M, respectively, which are 115 and 1660 times stronger than those previously measured under the same conditions for a single repeat of a mouse salivary proline‐rich protein. The increase in affinity is ascribed to intramolecular secondary interactions, which are strengthened by the rigidity of the interacting molecules.