Inhibitory effect of Orange Yellow S on the structure and the function of catalase: Spectroscopic methods combined with theoretical studies

The study on the conformational and functional changes of catalase as an antioxidant defense system of the liver, in the presence of various compounds has been very important. In the present study, the interaction between Orange Yellow S and catalase were investigated using multiple spectroscopic (fluorescence, ATR-FTIR, and UV–vis) and molecular docking methods. Orange Yellow S; OYS is a synthetic food additive that have been used widely in food industry. Results of in vitro kinetics study demonstrated that OYS leaded to a significant reduction in the catalase activity through competitive inhibition mechanism. Also, the fluorescence quenching data showed a gradual decrease in the intrinsic fluorescence emission at two different temperatures by a dynamic mechanism and an alteration in the micro-region around aromatic amino acids (tryptophan (Trp) and tyrosine (Tyr)). Thermodynamic parameters were illustrated that OYS has more than one binding site on BLC. UV–vis and ATRFTIR spectroscopic have been used for monitoring the changes in secondary structure of the enzyme. Molecular docking study results were in good agreement with experimental data. For the assurance of consumer health, it is important to control OYS in foodstuff. Because it may lead to several serious health problems by affecting on macromolecules.

Keywords:

Bovine liver catalase , Orange Yellow S , Food dyes