Binding Mechanism Between Iron‐Related Proteins (Catalase and Transferrin) and Favipiravir

Abstract The study of protein‐drug interactions has become important in describing drug properties. Favipiravir ( Fav ) is an RNA polymerase inhibitor used to treat a wide range of influenza viruses. This drug, which is taken orally, can be quickly and widely absorbed in the body. Here, the interaction of Fav with two Fe‐related proteins, Catalase (CAT) and Transferrin (TF), was investigated by spectroscopic and molecular docking methods. The results showed that Fav can strongly interact with two Fe‐proteins and quench their intrinsic fluorescence through a static mechanism. The affinity of Fav to CAT and TF was almost close to each other and with the order of 10 6  M −1 ( K b  = 9.54 × 10 6  M −1 for Fav ‐TF and 10.71 × 10 6  M −1 for Fav ‐CAT at 310 K). The binding of the Fav to the proteins changed their conformation to some extent and the stability of the proteins decreased. Molecular docking results showed the best binding site of Fav on both TF and CAT along with the types of interactions involved. Hydrogen bonds and van der Waals interactions were the predominant forces observed between Fav and the two proteins. Accessible surface area strongly supports the successful binding of Fav to both TF and CAT.