Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,f...Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,fluorescence spectra,circular dichroism(CD),and Fourier transform infrared(FT-IR)spectra at a molecular level.Fluorescence spectra showed that PHL quenches the pepsin/trypsin by static quenching.Thermodynamic parameters indicated that PHL binds to pepsin mainly through hydrogen bonds and van der Waals forces,and that of trypsin was electrostatic forces.The ground state complexes PHL and protease have a moderate affinity of 105 L/mol PHL binds more strongly to trypsin than to pepsin.CD and FT-IR spectra results showed that pepsin/trypsin decreased theβ-sheet content and slightly changed its secondary structure upon PHL.These experimental results are mutually verified with the predicted computer-aid simulation results.Upon PHL and trypsin binding,the antioxidant capacity of PHL was elevated.Nevertheless,the antioxidant capacity of PHL was decreased after binding to pepsin.This work elucidates the binding of PHL binding mechanisms to pepsin/trypsin and provides useful information for the digestion of PHL to improve the application of PHL in food processing.展开更多
Hispidin is a pyranone compound found in edible and medicinal mushrooms of the Phellinus and Inonotus genera.This investigation used fluorescence spectroscopy,UV absorption spectroscopy,and molecular docking to examin...Hispidin is a pyranone compound found in edible and medicinal mushrooms of the Phellinus and Inonotus genera.This investigation used fluorescence spectroscopy,UV absorption spectroscopy,and molecular docking to examine the interaction of hispidin with pepsin.The Stern-Volmer method was used to perform the fluorescence quenching measurements at different temperatures(298 K,303 K,and 310 K).According to the findings,hispidin induced a static quenching mechanism in pepsin that resulted in the creation of a hispidin-pepsin complex with binding constants(Ka)ranging from 9.56×10^(4) to 3.45×10^(5) L mol^(-1).The positive values ofΔH(84.6 kJ mol-1)andΔS(337.9 J mol^(-1) K^(-1))demonstrated that hydrophobic forces contributed to forming the hispidin-pepsin complex.The findings of UV-vis absorption,synchronous fluorescence,and 3D fluorescence spectraspectra demonstrated that hispidin altered the conformation and microenvironment of pepsin.According to the analysis of molecular docking,hispidin got into the pepsin's active cavity.The research clarifies the molecular mechanisms by which hispidin binds to pepsin and helps understand its possible biological activity in vivo.展开更多
基金supported by the National Natural Science Foundation of China(21808020)the Applied Basic Research Program of Science&Technology Department of Sichuan Province(2018JY0151)。
文摘Phlorizin(PHL)is a natural compound with strong antioxidant properties mainly found in apples.In this paper,the interaction mechanism of PHL with pepsin and trypsin was comparatively evaluated by computer simulation,fluorescence spectra,circular dichroism(CD),and Fourier transform infrared(FT-IR)spectra at a molecular level.Fluorescence spectra showed that PHL quenches the pepsin/trypsin by static quenching.Thermodynamic parameters indicated that PHL binds to pepsin mainly through hydrogen bonds and van der Waals forces,and that of trypsin was electrostatic forces.The ground state complexes PHL and protease have a moderate affinity of 105 L/mol PHL binds more strongly to trypsin than to pepsin.CD and FT-IR spectra results showed that pepsin/trypsin decreased theβ-sheet content and slightly changed its secondary structure upon PHL.These experimental results are mutually verified with the predicted computer-aid simulation results.Upon PHL and trypsin binding,the antioxidant capacity of PHL was elevated.Nevertheless,the antioxidant capacity of PHL was decreased after binding to pepsin.This work elucidates the binding of PHL binding mechanisms to pepsin/trypsin and provides useful information for the digestion of PHL to improve the application of PHL in food processing.
基金This work was financially assisted by the Natural Science Foundation of Guangdong Province(2021A1515010615,2022A1515012520)Special Fund for Science and Technology Innovation Strategy of Guangdong Province(2021S0052,2022DZXHT015,2023S003040,2023S002024,2022S035)Projects of Talents Recruitment of GDUPT(519030).
文摘Hispidin is a pyranone compound found in edible and medicinal mushrooms of the Phellinus and Inonotus genera.This investigation used fluorescence spectroscopy,UV absorption spectroscopy,and molecular docking to examine the interaction of hispidin with pepsin.The Stern-Volmer method was used to perform the fluorescence quenching measurements at different temperatures(298 K,303 K,and 310 K).According to the findings,hispidin induced a static quenching mechanism in pepsin that resulted in the creation of a hispidin-pepsin complex with binding constants(Ka)ranging from 9.56×10^(4) to 3.45×10^(5) L mol^(-1).The positive values ofΔH(84.6 kJ mol-1)andΔS(337.9 J mol^(-1) K^(-1))demonstrated that hydrophobic forces contributed to forming the hispidin-pepsin complex.The findings of UV-vis absorption,synchronous fluorescence,and 3D fluorescence spectraspectra demonstrated that hispidin altered the conformation and microenvironment of pepsin.According to the analysis of molecular docking,hispidin got into the pepsin's active cavity.The research clarifies the molecular mechanisms by which hispidin binds to pepsin and helps understand its possible biological activity in vivo.
