Improving enzymatic performance of antioxidant enzyme catalase in combination with [Mn (phen)2Cl.H2O]Cl.tu complex

Abstract

Efforts to synthesize metal complexes that have good biological potency, such as anti‐cancer or antioxidant properties, have expanded. In this study, an Mn complex containing 1,10‐phenanthroline (phen) and thiourea (tu), [Mn (phen)2Cl.H2O]Cl.tu, was selected, and its interaction with the antioxidant enzyme bovine liver catalase (BLC) was evaluated by spectroscopic and molecular docking methods. Our results showed that Mn complex interacts with BLC via a dynamic, endothermic, entropy‐driven mechanism. The binding constants (Kb) of BLC‐Mn complex were 0.62 ± 0.01, 0.73 ± 0.03, and 2.62 ± 0.09 × 103 M−1 at 303, 310, and 317 K, respectively. During complex interaction with catalase, the most important forces involved were hydrophobic forces. Considering that the quenching rate of tryptophan (Trp) was higher than that of tyrosine (Tyr), it can be concluded that Trp is closer to the Mn complex interaction site than Tyr. The CD spectra showed that the BLC secondary structure became more stable in the presence of the Mn complex and could be a reason for improving the catalytic activity of this enzyme. Molecular docking was used to predict that the Mn complex is able to bind to BLC and to identify specific residues. In general, the above Mn complex can be further evaluated as a suitable synthetic metallodrug due to its good antioxidant activity and binding function that improves the enzymatic activity of catalase.