Inhibition of Lysozyme by Taurine Dibromamine

Title:Inhibition of Lysozyme by Taurine Dibromamine

Volume: 20 Issue: 11

Author(s): M. S. Petronio and V. F. Ximenes

Affiliation:

Keywords: Eosinophils, hypobromous acid, hypochlorous acid, lysozyme, neutrophils, taurine dibromamine.

Abstract: Hypobromous acid (HOBr) is a powerful oxidant produced by stimulated neutrophils and eosinophils. Taurine, a non-protein amino acid present in high amounts in the leukocytes, reacts instantaneously with HOBr leading to their haloamine derivative taurine dibromamine (Tau-NBr₂). Lysozyme is a bactericidal enzyme also present in leukocytes and in secretory fluids. The inhibition of lysozyme is a pathway for bacterial proliferation in inflammatory sites. Here, we investigated the inhibition of the enzymatic activity of lysozyme when it was submitted to oxidation by Tau-NBr₂. We found that the oxidation of lysozyme by Tau-NBr₂ decreased its enzymatic activity in 80%, which was significant higher compared to the effect of its precursor HOBr (30%). The study and comparison of Tau-NBr₂ and HOBr regarding the alterations provoked in the intrinsic fluorescence, synchronous fluorescence, resonance light scattering and near and far-UV circular dichroism spectra of lysozyme and oxidized lysozyme revealed that tryptophan residues in the active site of the protein were the main target for Tau-NBr₂ and could explain its efficacy as inhibitor of lysozyme enzymatic activity. This property of Tau-NBr₂ may have pathological significance, since it can be easily produced in the inflammatory sites.

Cite this article as:

Petronio S. M. and Ximenes F. V., Inhibition of Lysozyme by Taurine Dibromamine, Protein & Peptide Letters 2013; 20 (11) . https://dx.doi.org/10.2174/0929866511320110007