Interactions and effects of food additive dye Allura red on pepsin structure and protease activity; experimental and computational supports

Abstract

Background and purpose: Today, color additives such as Allura red (AR) are widely used in different kinds of food products. Pepsin is a globular protein that is secreted as a digestive protease from the main cells in the stomach. Because of the important role of pepsin in protein digestion and because of its importance in digestive diseases the study of the interactions of pepsin with chemical food additives is important. Experimental approach: In this study, the interactions between AR and pepsin were investigated by different computational and experimental approaches such as ultraviolet and fluorescence spectroscopy along with computational molecular modeling. Findings/Results: The experimental results of fluorescence indicated that AR can strongly quench the fluorescence of pepsin through a static quenching. Thermodynamic analysis of the binding phenomena suggests that van der Waals forces and hydrogen bonding played a major role in the complex formation. The results of synchronous fluorescence spectra and furrier transformed infra-red (FTIR) experiments showed that there are no significant structural changes in the protein conformation. Also, examined pepsin protease activity revealed that the activity of pepsin was increased upon ligand binding. In agreement with the experimental results, the computational results showed that hydrogen bonding and van der Waals interactions occurred between AR and binding sites. Conclusion and implications: From the pharmaceutical point of view, this interaction can help us to get a deeper understanding of the effect of this synthetic dye on food digestion.

Effect of Azo Dye Red 2G on Human Gamma Globulin using Multi-Spectroscopic and Docking Studies

“…The absorption intensity of the R2G-HGG samples increases with higher R2G concentrations and there are no significant changes in the peak location. red 2G (1) 0.0, (2) 0.2, (3) 0.4, (4) 0.6, (5 These results indicated that the microenvironment around the amino acid residues in HGG remains unchanged upon the interaction with R2G and a lack of significant conformational changes in the protein structure [14]. An increase in the absorbance of HGG is due to the formation of a ground-state combination between red 2G and HGG [15].…”

Insights on the conformation and appropriate drug-target sites on retinal IMPDH1 using the 604-aa isoform lacking the C-terminal extension

“…The present study adopted a combination of computational biochemistry and experimental engineering ( 31 32 33 ) to investigate the potential interactions of the N-terminal peptide and the resultant conformational changes. We performed proteolysis on a recombinant 604-aa isoform lacking a C-terminal peptide and simulated the molecular dynamics of its modelled dimer.…”

Risk assessment of azo dyes as food additives: Revision and discussion of data gaps toward their improvement

“…When used in conjunction with the natural dye curcumin, the synergistic effect increases the stability of the Sunset Yellow FCF-catalase complex and the inhibition of enzyme activity (Khataee et al, 2019). In contrast, the van der Waals and hydrogen bonds of Allura Red AC form a stable complex with pepsin, which increases the enzyme activity (Balaei et al, 2021). Tartrazine induced DNA damage due to high binding capacity to hydrogen acceptors (nON = 13), which suggests interference with DNA hydrogen bonds (Floriano et al, 2018).…”

“…It also inhibits fibrillogenesis due to its binding to β‐lactoglobulin (Patel et al., 2019). Investigating interactions between exogenous agents and biomacromolecules, such as DNA and proteins, is essential due to the possibility of interference in body homeostasis (Balaei et al., 2021). The protein with the highest concentration in human plasma is serum albumin, which binds azo dyes (tartrazine, Sunset Yellow FCF, Allura Red AC, and carmoisine) tightly via hydrogen bonds and van der Waals forces (Masone & Chanforan, 2015; Wu et al., 2015).…”

“…The possibility of tracking probable interactions and determining which food components will have a greater affinity for synergistic or antagonistic actions is an important ally to guide the risk assessment of azo dyes. This type of approach is used with human serum albumin and azo dyes for toxicological effect studies (Masone et al., 2015; Khataee et al., 2019; Balaei et al., 2021).…”