Investigation of the interactions between indoIe-3-acetic acid and catalase: A spectroscopic study in combination with second-order calibration and molecular docking methods

摘要

The interactions between indole-3-acetic acid (IAA) and the important antioxidant enzyme catalase (CAT) have been studied by Ultraviolet-visible (UV-vis) and fluorescence spectroscopic methods. The decrease of the absorption intensity of CAT at 270 nm and 407 nm in UV-vis spectra with the addition of IAA indicated the interactions between CAT and IAA. The three-way excitation-emission matrix spectra combined with parallel factor analysis (PARAFAC) was used to provide the individual concentration information of IAA, CAT, and IAA-CAT in the reaction system. The PARAFAC analysis showed that a 1 : 1 IAA-CAT complex formed at the equilibrium point. Constant wavelength synchronous fluorescence spectrometry (SFS) showed that the binding of IAA resulted in the micro-environment changes around tryptophan (Trp) and tyrosine (Tyr) residues. Molecular docking studies provide a good structural basis to explain the experimental results. This work is valuable for providing a deeper insight into the interaction mechanism of IAA with CAT.