Binding mechanism of maltol with catalase investigated by spectroscopy, molecular docking, and enzyme activity assay

Abstract

Maltol is a flavor additive that is widely used in the daily diet of humans, and its biosafety attention is concomitantly increasing. Catalase (CAT) is an antioxidant enzyme to maintain homeostasis in the tissue's environment of human body and protect cells from oxidative damages. The adverse effects of maltol to CAT activity within mouse hepatocytes as well as the structural and functional changes of CAT on molecular level were investigated by multiple spectroscopy techniques, enzyme activity experiments, and molecular docking. Results suggested that when the maltol concentrations reached to 8 × 10 −5 mol L −1 , the viability of hepatocytes decreased to 93%, and CAT activity was stimulated by maltol to 111% than the control group after exposure for 24 hours. Changes in CAT activity on molecular level were consistent with those on cellular level. The fluorescence quenching of CAT by maltol was static with the forming of maltol-CAT complex. Moreover, ultraviolet-visible (UV-visible) absorption, synchronous fluorescence, and circular dichroism (CD) spectra reflected that the presence of maltol caused conformational change of CAT and made the CAT molecule skeleton loose and increased α-helix of CAT. Maltol mainly bound with CAT through hydrogen bond, and binding site that is near the heme ring in the enzyme activity center did not interact with its main amino acid residues. This study explores the combination between maltol and CAT, providing references for evaluating health damages caused by maltol.

Simvastatin ameliorates oxidative stress levels in HepG2 cells and hyperlipidemic rats

“…1 . The review of the literature shows that catalase binds with other compounds and simvastatin binds only to inhibitors of HMG-CoA reductase in particular ( Yekta et al., 2017 ; Huo et al., 2020 ; Shahraki et al., 2020 ; Nazir et al., 2018 ). However, the binding of simvastatin with catalase has never been reported earlier.…”

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

“…Peak 1 (λ ex = 280 nm, λ em = 330 nm) is the characteristic peak of Tyr, Trp, and Phe; peak 2 mainly related to the fluorescence changes of the polypeptide backbone. [ 39 ] As can be seen, in addition to the decrease in intensity, peaks 1 and 2 have also shown a shift in the maximum wavelength. Such observations could be a reason for the unfolding of the BLC backbone after interaction with the Mn complex and would also confirm the UV–Vis results.…”

In Vitro and In Silico Antioxidant Activity and Molecular Characterization of Bauhinia ungulata L. Essential Oil

“…Thus, the volatile constituents with the highest concentration in EOBU, α‐bisabolol and β‐caryophyllene were anchored in the human CAT enzyme binding pockets (Figure 5). Maltol was used as a positive control, as it increases CAT activity and is already established in the literature [41] . α‐Bisabolol showed good interaction with CAT, where it obtained a mean value of −5.7±0.4 Kcal.mol −1 and β‐caryophyllene with a mean value of −6.1±0.5 Kcal.mol −1 .…”

“…Maltol was used as a positive control, as it increases CAT activity and is already established in the literature. [41] α-Bisabolol showed good interaction with CAT, where it obtained a mean value of À 5.7 � 0.4 Kcal.mol À 1 and β-caryophyllene with a mean value of À 6.1 � 0.5 Kcal.mol À 1 . The Maltol control showed an average value of À 4.4 � 0.4 Kcal.mol À 1 .…”