First, excessive Cu inhibited microbe
growth and multiplications, thus affecting enzyme synthesis and
secretion of microbes and then resulting in decreased enzyme
activity (Pages et al., 2007; Rossbach et al., 2000).
Second, Cu combined with functional groups (sulfydryl and imidazolyl and others)
in the active centers of enzyme molecules through coordinate
bonds to form stable complexes, thus competing with enzyme substrates (Guo et al., 2011)