Peptide-polyphenol

From the concentration dependence of the polyphenol chemical shifts as a function of the polyphenol concentration in the absence and presence of peptide, it is clear that polyphenol self-association is only weakly affected by the peptide. Thus, peptide-polyphenol binding probably involves noncovalent polyphenol oligomers that are more effective than the corresponding monomers at developing interactions with a second peptide molecule to trigger precipitation. 

Richard T, Lefeuvre D, Descendit A, Quideau S, Monti JP. Recognition characters in peptide-polyphenol complex formation. Biochim Biophys Acta Gen Subj. 2006 1760(6) 951-958. 

MS/MS Analysis of Peptide-Polyphenols Supramolecular Assemblies Wine Astringency Approached by ESI-IT-MS... 

Flavonoid and peptide solutions were mixed immediately before infusion into the mass spectrometer ion source. The peptide/polyphenol molar ratio was 1 3 for IB7i4. So as to obtain a wine like final solution, 222.5 iL of the pure peptide solution (22.5 pmol L in water) were mixed with 27.5 iL of the polyphenol solution... 

For ERMS experiments, precursor ions corresponding to peptide/polyphenol complexes with a 1 1 stoichiometry were selected and activated at different percentages of normalized collision energy [%NCE, Equation 6.1] in steps of 0.1% NCE for 30 ms. 

Therefore, so as to avoid the uncertainties associated with thepossible spatial arrangements of polyphenols within the peptide-polyphenol complex, CID experiments were realized solely with peptide-polyphenol complexes having a 1 1 stoichiometry. 

DE50 Values were Determined as Described Under Section 6.3.2. Methods for 1 1 Peptide Polyphenol Complexes. Relative Standard Deviations Never Exceeded 0.001 and are Therefore, not Reported in the Table... 

For an application of the NCE method see Volume 5, Chapter 6 MS/MS Analysis of Peptide-polyphenols Supramolecular Assemblies Wine Astringency Approached by ESl-lT-MS by Benort Piet and Jean-Marie Schmitter. 

CHARLTON A J, BAXTER N J, KHAN M L, MOIR A J, HASLAM E, DAVIES A P, WILLIAMSON M P (2002) Polyphenol/peptide binding and precipitation. J Agric Food Chem. 50 1593-601. 

A variation on the Thompson and Forward method was developed in which a HA peptide or peptide-like material (e.g., gelatin, gliadin, polyproline, or soluble polyvinylpyrrolidone) is added to a sample to induce haze in proportion to the amount of HA polyphenol it contains (Siebert et al., 1996a). This gives little response in beer, which contains very little HA polyphenol, and causes much larger haze increases in fruit juices and wine. 

This was shown to occur because silica binds to the same features in polypeptides that polyphenols do (peptidically linked proline Siebert and Lynn, 1997b) (see the concept in Fig. 2.21). In contrast, in unstabilized apple juice, silica removes only on the order of 20% of the HA protein... 

Recently, proteolytic enzymes that cleave peptide bonds only adjacent to proline were introduced (Lopez and Edens, 2005). Since proline is involved in the polyphenol-binding sites and there is little proline in the foam-active proteins, these enzymes are specific for haze proteins and do little damage to foam proteins. 

Hatano, T., Yoshida, T., and Hemingway, R.W., Interaction of flavonoids with peptides and proteins and conformations of dimeric flavonoids in solution. In Plant Polyphenols 2. Chemistry, Biology, Pharmacology, Ecology (eds G.G. Gross, R.W. Hemingway, T. Yoshida, and S.J. Branham), Kluwer Academic/Plenum Publisher, New York, 1999, p. 509. 

Resveratrol shows a direct inhibitory activity on heart fibroblasts and suppresses the spreading of heart fibrose (05MI1131). The vasoconstrictor peptide endothelin (ET-1) is controlled in its biosynthesis by polyphenols, and especially by resveratrol. Only 5 pmol causes an endothelin-depen-dent vasodilatation and lowers blood pressure (88NAT411, 01MI152, 01NAT863,06NAT566). 

Effects of Tea Extracts and Related Polyphenols against Toxicity Induced by A(3 Peptides... 

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