Intrinsic Fluorescence Characteristics of Apomyoglobin Adsorbed to Microparticulate Silica

The intrinsic fluorescence of sperm whale apomyoglobin was utilized as the probe in a study of protein adsorption, desorption, and conformational behavior on a series of microparticulate silica gels. The results indicate that adsorption is rapid and largely irreversible. The degree of protein unfolding that takes place upon adsorption is dependent on the pH of the contact buffer. The tryptophans in the pH 4.0 surface conformer are more exposed and interact to a greater extent with the interfacial environment than in the pH 7.5 surface conformer. Partial, reversible refolding of the protein in the sorbed state is observed with a change in the pH of the contact buffer.