TY  - JOUR
A1  - Rawel, Harshadrai Manilal
A1  - Frey, Simone K.
A1  - Meidtner, Karina
A1  - Kroll, Jürgen
A1  - Schweigert, Florian J.
T1  - Determining the binding affinities of phenolic compounds to proteins by quenching of the intrinsic tryptophan fluorescence
JF  - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology
N2  - 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.
KW  - amylase activity
KW  - green tea phenols
KW  - protein-phenol binding
KW  - saliva proteins
KW  - tryptophan quenching
Y1  - 2006
U6  - https://doi.org/10.1002/mnfr.200600013
SN  - 1613-4125
VL  - 50
IS  - 8
SP  - 705
EP  - 713
PB  - Wiley
CY  - Weinheim
ER  -