Spectral studies on the interaction between Cu2+ and urease

The interactions of Cu2+ with urease were investigated by fluorescence, UV/vis, CD, synchronous fluorescence, and three-dimensional fluorescence spectra techniques. Cu2+ effectively quenched the intrinsic fluorescence of urease via static quenching. The binding constant KA, the binding site n and the thermodynamic parameters are obtained. The process of binding Cu2+ to urease was a spontaneous molecular interaction procedure with electrostatic interaction. The conformation of urease was discussed by UV/vis, CD, synchronous and three-dimensional fluorescence techniques.

The fluorescence intensity of urease decreased obviously and urease molecular could bind with Cu2+ by mainly electrostatic interaction. The results of multi-spectra methods indicated that Cu2+ induced some unfolding of the polypeptides of urease and changed the conformation of urease. The binding studies of Cu2+ with urease have toxicological importance and provide spectral methods to explore the biological toxicity of Cu2+ to the target of other enzymes in soil.Figure optionsDownload as PowerPoint slideHighlights
► Binding interactions of urease with Cu2+ were investigated.
► The electrostatic interaction stabilizes the urease–Cu2+ complex.
► The presences of Cu2+ could alter the second structure of urease.
► The 3D fluorescence spectra of urease–Cu2+ system are showed in paper.