Stabilization of yeast cytochrome C covalently immobilized on fused silica surfaces

The surface-enhanced conformational stability of yeast cytochrome c (YCC) covalently immobilized on a fused silica prism with heterobifunctional cross-linkers has been studied by attenuated total reflection absorption spectroscopy using the Soret band of the heme prosthetic group as a probe. Comparison of the results to those of horse cytochrome c physisorbed on the same substrate as well as to the corresponding proteins in solution indicates that the surface plays a significant role in stabilizing the native conformation of the surface-bound YCC. Unfolding to extended configurations was so hindered that the native conformation of the covalently immobilized protein is essentially unaffected by the presence of denaturants such as methanol and 1-propanol.