Inhibition of lysozyme by taurine dibromamine

• Autor(a) principal: Petrônio, M. S. [UNESP]
• Data de Publicação: 2013
• Outros Autores: Ximenes, V. F. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.2174/0929866511320110007; http://hdl.handle.net/11449/227314
• topic: Eosinophils; Hypobromous acid; Hypochlorous acid; Lysozyme; Neutrophils; Taurine dibromamine

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. © 2013 Bentham Science Publishers.