Fluorescence study on the interaction between apoCopC and cupric

The interaction between apoCopC and cupric was investigated by fluorescence spectra, in phosphate (20 mmol/L) buffer at pH 6.0. Results suggest that the environment is measured to be hydrophobic completely around tryptophan (83). At the same time, apoCopC fluorescence at 320 urn was significantly quenched with the addition of cupric and the 1:1 stoichiometric ratio of apoCopC to cupric was confirmed by fluorescence. In addition, the conditional binding constants were calculated to be KCu-Cope = (1.8 +/- 0.58) x 10(13) mol(-1) L on the basis of the results of fluorescence titration curves. The apoCopC has the ability to bind specifically cupric ion.