Adsorption study of heme proteins on SBA-15 mesoporous silica with pore-filling models

The Langmuir-type adsorption of myoglobin occurred with monolayer coverage of the inner surface mesopore channels of SBA-15. Myoglobin occupation of the pores was calculated as ca. 50% based on N2 adsorption/desorption isotherms. Pore-filling models revealed that myoglobin molecules are well packed in the pores. The maximum adsorption was observed near the isoelectric point of myoglobin, suggesting the important role of suppression of electric repulsion between the proteins and/or between the protein and the adsorbent. FT-IR spectroscopic studies confirmed that the myoglobin is stable even after the adsorption. The results obtained are comparable with those observed for another redox protein, cytochrome c.