Noncompetitive Inhibition of Bovine Liver Catalase byLawsone: Kinetics, Binding Mechanism and in silico ModelingApproaches

Lawsone (2-hydroxy-1,4-naphtoquinone; law), as a naphthoquinone derivative, is thebiologically active component of henna leaves. in this study, the structural and functional effectsof law on bovine liver catalase (blc), has been studied utilizing ultraviolet-visible (uv-vis)absorption, fluorescence, and atr-ftir spectroscopic techniques, and molecular dockingapproach. in-vitro kinetic study showed that by adding gradual concentrations of law, catalaseactivity was significantly decreased through noncompetitive inhibition mechanism. uv–visand atr-ftir spectroscopic results illustrated that additional concentration of law lead tosignificant change in secondary structure of the enzyme.the fluorescence spectroscopic results atdifferent temperatures indicated that law quenches the intrinsic fluorescence of blc by dynamicmechanismand there is just one binding site for law on bcl. changing the micro-environmentnearby two aromatic residues (tryptophan (trp) and tyrosine (tyr)) were resulted from synchronousfluorescence. the thermodynamic parameters were implied that the hydrophobic bindings havea significant impress in the organization of the law-catalase complex. molecular docking datain agreement with experimental results, confirmed that hydrophobic interactions are dominant.inhibition of enzyme activity by law, showed that along withits helpful effects as ananti-oxidantcompounds, the side effects of law should not be overlooked.