The unfolding process of the Blue Copper Protein (BCP) rusticyanin (Rc) has been studied using a wide variety of biochemical techniques. Fluorescence and CD spectroscop-ies reveal that the copper ion plays an essential role in sta-bilizing the protein and that the oxidized form is more efficient than the reducedspecies in this respect. Theaddition of guanidinium chloride to Rc samples produces aggrega-tion of the protein. Gel filtration chromatography and glutaraldehyde cross-linking experiments confirm the for-mation of such aggregates. .
