Noncovalent interactions between Quinoline yellow and trypsin: In vitro and in silico methods

These days, synthetic colors are extensively used in many products, so it is essential to get more information about their side effects. We selected Quinoline yellow as an edible color and trypsin as one of the essential enzymes of our body in our study. Several techniques such as fluorescence spectrophotometry, UV-Vis spectroscopy, molecular dynamics simulation, and molecular docking were used to investigate the effects of Quinoline yellow on the structure and activity of trypsin. The results of UV- Vis spectroscopy and fluorescence spectrophotometry indicated that Quinoline yellow could result in a reduction in absorption and intrinsic fluorescence of the enzyme. The results obtained by fluorescence spectroscopy showed a hypochromism shift and a static form of quenching in the presence of this color. Furthermore, the thermal stability study illustrated that Quinoline yellow (until 0.056 mM) increases the T-m point of trypsin by about 5C. The kinetics study indicated that the V-max value of trypsin in the presence of Quinoline yellow (0-0.0275 mM) increases from 0.0002 to 0.01 mmol.s(-1). Finally, the computational study results confirmed that the trypsin could be more compact in the existence of Quinoline yellow. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, the effects of Quinoline yellow on the structure and activity of trypsin were investigated using various techniques. The results indicated that Quinoline yellow reduced absorption and intrinsic fluorescence of the enzyme, increased its thermal stability and catalytic ability, and resulted in a more compact structure.