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Determining the binding affinities of phenolic compounds to proteins by quenching of the intrinsic tryptophan fluorescence
- The noncovalent binding of selected phenolic compounds (chlorogenic-, ferutic-, gallic acid, quercetin, rutin, and isoquercetin) to proteins (HSA, BSA, soy glycinin, and lysozyme) was studied by an indirect method applying the quenching of intrinsic tryptophan fluorescence. From the data obtained, the binding constants were calculated by nonlinear regression (one site binding; y = Bx/k + x). It has been reported that tannins inhibit human salivary amylase and that these complexes may reduce the development of cariogenic plaques. Further, amylase contains two tryptophan residues in its active site. Therefore, in a second part of the study involving 31 human subjects, evidence was sought for noncovalent interactions between the phenols of green tea and saliva proteins as measured by the fluorescence intensity. Amylase activity was determined before and after the addition of green tea to saliva of 31 subjects. Forty percent of the subjects showed an increase in amylase activity contrary to studies reporting only a decrease in activity.The noncovalent binding of selected phenolic compounds (chlorogenic-, ferutic-, gallic acid, quercetin, rutin, and isoquercetin) to proteins (HSA, BSA, soy glycinin, and lysozyme) was studied by an indirect method applying the quenching of intrinsic tryptophan fluorescence. From the data obtained, the binding constants were calculated by nonlinear regression (one site binding; y = Bx/k + x). It has been reported that tannins inhibit human salivary amylase and that these complexes may reduce the development of cariogenic plaques. Further, amylase contains two tryptophan residues in its active site. Therefore, in a second part of the study involving 31 human subjects, evidence was sought for noncovalent interactions between the phenols of green tea and saliva proteins as measured by the fluorescence intensity. Amylase activity was determined before and after the addition of green tea to saliva of 31 subjects. Forty percent of the subjects showed an increase in amylase activity contrary to studies reporting only a decrease in activity. The interactions of tannin with amylase result in a decrease of its activity. It still remains to be elucidated why amylase does not react uniformly under conditions of applying green tea to saliva. Further, in terms of using phenols as caries inhibitors this finding should be of importance.…
Verfasserangaben: | Harshadrai Manilal RawelORCiDGND, Simone K. Frey, Karina MeidtnerORCiDGND, Jürgen KrollGND, Florian J. SchweigertORCiDGND |
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DOI: | https://doi.org/10.1002/mnfr.200600013 |
ISSN: | 1613-4125 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/16835869 |
Titel des übergeordneten Werks (Englisch): | Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology |
Verlag: | Wiley |
Verlagsort: | Weinheim |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2006 |
Erscheinungsjahr: | 2006 |
Datum der Freischaltung: | 10.06.2020 |
Freies Schlagwort / Tag: | amylase activity; green tea phenols; protein-phenol binding; saliva proteins; tryptophan quenching |
Band: | 50 |
Ausgabe: | 8 |
Seitenanzahl: | 9 |
Erste Seite: | 705 |
Letzte Seite: | 713 |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Ernährungswissenschaft |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 50 Naturwissenschaften / 500 Naturwissenschaften und Mathematik |
Peer Review: | Referiert |