title: Enhancement of Peroxidase Stability Against Oxidative Self-Inactivation by Co-immobilization with a Redox-Active Protein in Mesoporous Silicon and Silica Microparticles.
abstract: The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.
authors.affiliation: Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autónoma del Estado de México, Av. Univ. 1001, Col. Chamilpa, Cuernavaca, Morelos, 62209, Mexico.
authors.forename: P
authors.initials: P
authors.lastname: Sahare
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, Cuernavaca, 62210, Morelos, Mexico.
authors.forename: M
authors.initials: M
authors.lastname: Ayala
authors.affiliation: Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de Mexico, Km. 107, Carretera Tijuana-Ensenada, Apdo. Postal 14, CP 22800, Ensenada, Baja California, Mexico.
authors.forename: R
authors.initials: R
authors.lastname: Vazquez-Duhalt
authors.affiliation: Instituto de Física, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.
authors.forename: U
authors.initials: U
authors.lastname: Pal
authors.affiliation: pSiMedica Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3SZ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Loni
authors.affiliation: pSiMedica Ltd, Malvern Hills Science Park, Geraldine Road, Malvern, Worcestershire, WR14 3SZ, UK.
authors.forename: L T
authors.initials: LT
authors.lastname: Canham
authors.affiliation: Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: I
authors.initials: I
authors.lastname: Osorio
authors.affiliation: Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autónoma del Estado de México, Av. Univ. 1001, Col. Chamilpa, Cuernavaca, Morelos, 62209, Mexico. vagarwal@uaem.mx.
authors.forename: V
authors.initials: V
authors.lastname: Agarwal
keywords: Auto-inactivation; Microparticles; Peroxidase; Porous silica; Porous silicon