Interaction between azo dye Acid Red 14 and pepsin by multispectral methods and docking studies

Area of Science:

• Biochemistry
• Molecular Biology
• Toxicology

Background:

• Synthetic azo dyes are widely used in various industries.
• Understanding dye-protein interactions is crucial for assessing biological safety.
• Pepsin is a key digestive protease involved in protein breakdown.

Purpose of the Study:

• To investigate the interaction mechanism between the azo dye Acid Red 14 and pepsin.
• To determine the binding parameters and thermodynamic properties of this interaction.
• To evaluate the impact of Acid Red 14 on pepsin's structure and enzymatic activity.

Main Methods:

• Fluorescence spectroscopy to study quenching mechanisms and binding constants.
• UV-vis spectroscopy to monitor spectral changes.
• Circular dichroism to assess structural alterations in pepsin.
• Molecular docking to predict binding sites and interactions.

Main Results:

• Acid Red 14 exhibited strong static quenching of pepsin's intrinsic fluorescence.
• The interaction is spontaneous, driven by hydrogen bonding and van der Waals forces.
• Acid Red 14 binding caused minor changes in pepsin's secondary and tertiary structure.
• Hydrogen bonds formed between the dye and Tyr-189 and Thr-218 residues.
• Pepsin activity was inhibited upon binding with Acid Red 14.

Conclusions:

• Acid Red 14 interacts with pepsin, leading to inhibition of its enzymatic activity.
• The findings provide insights into the potential biological safety of Acid Red 14 concerning digestive proteases.
• This research offers a method for evaluating the safety of dyes on protein structures and functions.