Binding interactions of a series of sulfonated water-soluble resorcinarenes with bovine liver catalase

Abstract Resorcinarenes are macrocyclic molecules that can bind different molecules in a supramolecular fashion. There are some sulfonated water-soluble derivatives that have been investigated to bind proteins avoiding fibrillation. The interaction with enzymes such as catalase (CAT) allows the interpretation of the possible effects of the use of resorcinarenes on human health or environmental applications. The interaction of five sulfonated resorcinarenes with different chemical structures was investigated by using different biophysical methods. The results of the spectroscopic experiments (fluorescence, synchronous fluorescence, and Uv-vis spectrophotometry) show different degrees of structural change, indicating that the binding of the macrocycles that were studied causes alterations on the conformation of CAT. The resorcinarenes reduce the activity of CAT in different extent, two macrocycles (named Na4EtRA and Na4PrRA, according to ethyl or propyl moieties at the lower pendant group) exhibit significant inhibition capacity (until ca. 70%). The study about inhibition types reveals a non-competitive mechanism for all the studied resorcinarenes. The docking calculations reveal that the macrocycles bond mainly to two domains of the CAT structure, which are not related with the active site.