Immobilization of cytochrome P-450 on MCM-41 with different silicon/aluminum ratios

The catalytic activity of two cytochrome P-450 (CYP450) isoforms (CYP2C9 and CYP2B4, 1.14.14.1) immobilized on a mesoporous material “MCM-41” synthesized with Si/Al ratios of ∞, 80 and 100 was evaluated. The amount of CYP2C9 and CYP2B4 immobilized in each material was different, due to isoform size, the number of hydrogen bonds and the electrostatic interactions between the aminoacid residues and the Lewis acid sites of the material. The catalytic activity of immobilized CYP2C9 and CYP2B4 took place without using cytochrome P-450 reductase; consequently MCM-41 participates in electron transfer through the Lewis acid sites. In addition, the catalytic activity of immobilized CYP2B4 on MCM-41 was similar to its free form when a Si/Al ratio of 100 was used. Finally, although the catalytic activity of immobilized CYP2C9 was also better on MCM-41 with a Si/Al ratio of 100, it maintained around 30% of the catalytic activity in relation to its free form.