The Met80Ala point mutation enhances the peroxidase activity of immobilized cytochrome c

The effects of replacement of the axial methionine 80 hemeligand with a non-coordinating alanine on the peroxidaseactivity of kaolinite-immobilized cytochrome c wereinvestigated at different pH values. The catalytic activity10 of the adsorbed mutant was found remarkably higher thanthat of wild-type cytochrome c. The pH dependence ofVmax and KM values is discussed in term of accessibility ofthe substrates to the metal center and surface charge ofkaolinite. Our approach, based on the combined use of15 adsorption on kaolinite and protein engineering, endowsthis bioinorganic interface with remarkable catalyticproperties.