ENZYME MIMICS BY HETEROGENEOUS NANOBIOCATALYSTS OF PEROXIDASE/MESOPOROUS MATERIALS

Heterogeneous peroxidase and peroxidase model enzymes were prepared based on ordered mesoporous materials (OMMs) and used successfully for organic synthesis purposes. Nanobiocatalysts consisting of hemin, microperoxidase-11 and peroxidase were obtained by immobilization of biocatalysts on ordered mesoporous materials (OMMs) of MCM41 and amine-modified FSM16. Performances of these peroxidase models examined by peroxidatic and biotransformation reactions. MCM41, FSM16 mesoporous silicate and their chemically modified samples were synthesized. Then the relevant nanobiocatalysts consisting of Fe(III)protoporphyrin(IX) (Hemin, Fe(III)PPIX), microperoxidase-11 and horseradish peroxidase were obtained via direct immobilization of the biocatalysts in the nanopores of amine modified OMMs. The prepared catalysts were characterized by XRD, ASAP and diffuse reflectance UV/Vis techniques. The performances of the obtained peroxidase model nanostructures were evaluated by some typical test reactions, such as oxidation of ABTS, O-methoxyphenol (guaiacol) and peroxidatic synthesis of indophenol and N-antipyryl-p-benzoquinoneimine.Kinetic parameters including initial reaction rates, rate constants, Vmax, turnover number, Michaelis constant and catalytic efficiency were obtained and compared to those of Fe(III)PPIX/MCM41 and homogeneous native horseradish peroxidase (HRP). Results showed that MP-11/NH2-FSM16 catalyst is able to mimic horseradish peroxidase with a Km value of 55.45±1.29 μM with respect to ABTS and guaiacol (as the reducing substrates of HRP). The prepared nanobiocatalysts showed high peroxidatic activity for oxidation and conversion of aromatic substrates.

کلیدواژه ها:

Mesoporous silica ، Microperoxidase-11 ، Nanobiocatalyst ، Modification