How a promising anti-cancer derivative of palladium consisting phen-imidazole ligand affects bovine liver catalase functionality

Abstract

Promising background of using Nobel metal complexes such as cisplatin in cancer therapy has been emerged as encourage for scientists to design new species with the outlook of finding acceptable alternatives holding less side effects. That’s why study of interactions of promising complexes with special targets such as enzymes seems necessary. As similarity between coordination chemistry of Pd(II) and Pt(II) has been an excuse for scientists to find an alternative to cisplatin, we investigated the biological effects of [Pd(dach)(FIP)](NO3)2 compound containing a novel phen-imidazole ligand, FIP, and diamino cyclohexane (dach) on bovine liver Catalase (BLC) structure and function. Due to UV–vis study, with an increase in palladium compound’s concentration to 30 μM, the enzymatic activity reduced gradually. Afterwards in higher concentrations remained constant at around 65%. Meanwhile Km, kcat and vmax followed an upward trend which confirm mixed inhibitory mechanism.Although based on fluorescence quenching measurements in 25 and 37 °C catalase activity changes slightly, three-dimensional environment surrounding chromophores of the enzyme structure changes considerably in the presence of palladium complex. According thermodynamic parameters of this interaction, it is believed that hydrophobic interactions are influential in the binding process. Furthermore, CD spectroscopy data revealed that Pd(II) complex makes the secondary structure of BLC less stable. Despite remarkable structural changes of BLC due to hydrophobic interactions with ligands, its function was not influenced considerably. The results might expand horizons of medicinal chemists who are looking for metallic compounds as anticancer drugs with fewer side effects.