Binding of selected phenolic compounds to proteins

Area of Science:

• Biochemistry and Molecular Biology
• Food Chemistry
• Nutraceutical Science

Background:

• Phenolic compounds are widely found in plants and possess various biological activities.
• Understanding their interaction with dietary proteins is crucial for food processing and bioavailability.
• Proteins such as human serum albumin (HSA), bovine serum albumin (BSA), soy glycinin, and lysozyme are common targets.

Purpose of the Study:

• To investigate the noncovalent binding of specific phenolic acids and flavonoids to different proteins.
• To quantify binding parameters including binding constants and the number of binding sites.
• To explore the influence of environmental factors (temperature, ionic strength, pH) on these interactions.

Main Methods:

• Direct methods: Hummel-Dreyer assay and size exclusion chromatography.
• Indirect methods: Utilizing intrinsic fluorescence properties of quercetin as a probe.
• Circular dichroism (CD) spectroscopy to assess protein structural changes.

Main Results:

• Calculated binding constants and number of binding sites for various phenolic compounds and proteins.
• Demonstrated that increased temperature, ionic strength, and decreased pH reduce phenolic compound binding.
• Circular dichroism revealed alterations in protein tertiary structure, while secondary structure remained unaffected.

Conclusions:

• Noncovalent interactions between phenolics and proteins are complex and sensitive to environmental conditions.
• Phenolic compounds can modulate protein structure, potentially impacting their functional properties.
• These findings contribute to understanding the behavior of phenolics in biological and food systems.