The interaction of proteins with [Hg(SCN)4]2- and [Zn(SCN)4]2-, interaction between protein and protein, interaction between protein and sodium heparin were investigated by absorption spectra, fluorescence spectra and resonance Rayleigh scattering (RRS) spectra. The reaction mechanism, binding mode, binding sites and the main interaction forces were studied through the changes in spectra. Additional, some new methods for the determination of protein or sodium heparin were established from the investigated s...