Fast photoreduction of a heme peptide encapsulated in nanostructured materials

Microperoxidase-11 has been immobilized on siliceous materials MCM-41 and SBA-15 and on amino-functionalized SBA-15. Resonance Raman spectroscopy has provided solid evidence that the exogenous species occupy the pores of the mesoporous silica materials. Photoreduction of the microperoxidase-11 Fe(III) center has been observed to occur in the immobilized samples and results in a long-lived stable reduced heme. Reoxidation of the heme occurs upon addition of oxygen, and the redox cycle can be repeated numerous times. The source of the electron resulting in reduction of the heme is proposed to originate from the silica matrix, and functionalization of silica surface is suggested to facilitate electron transfer to the heme.