Effects of oxidation of lysozyme by hypohalous acids and haloamines on enzymatic activity and aggregation.

摘要: Abstract Hen egg white lysozyme (HEL), an antibacterial enzyme, is a prototype protein for studying the physical and chemical events that underlie formation of amyloid fibril aggregates. Here, we studied alterations in enzymatic activity aggregation provoked by oxidation HEL hypochlorous acid (HOCl), hypobromous (HOBr), taurine chloramine (Tau–NHCl), monobromamine (Tau–NHBr), dibromamine (Tau–NBr 2 ). Addition only 4-fold molar excess Tau–NHBr or Tau–NBr to caused complete depletion its intrinsic fluorescence, whereas HOCl HOBr 40%–50% bleaching. Tau–NHCl was unable oxidize lysozyme. The selective effect bromamines on tryptophan residues had direct activity; were about two-fold more effective as inhibitors than precursors. regarding protein, which evidenced increased turbidity, Rayleigh scattering, anisotropy. aggregates presented spectroscopic properties suggested fibrils, measured thioflavin assay. In conclusion, capacity bactericidal could represent role exacerbation pulmonary infection, since leukocytes are rich sources both HOBr. Moreover, just small hypohalous acids, condition be found inflammatory sites, may new pathway initiation aggregation.