Herein we describe, for the first time, the covalent immobilization of catalase (CAT) on functionalized graphene surfaces (G) exploiting the azlactone chemistry for the post-functionalization of graphene-based materials. The structure, morphology and chemical composition of catalase immobilized on graphene (CAT-G) have been investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). The biological responses such as catalytic activity, cellular uptake, internalization pathway, ability to protect lymphocytes from oxidative stress induced by H2O2 together with the unforeseen ability to increase the lifetime of the free catalase in solution have been deeply investigated. From our studies, it emerges that the behavior of CAT covalently linked to modified graphene depends on CAT/G ratio that affects the secondary structure and the tetramer stability of CAT. In order to support the experimental results, we have also investigated the behaviors of two appropriately designed model systems, named CAT-surfer and CAT-skier, by molecular dynamics calculations. These in silico results parallel the experimental ones demonstrating our hypothesis that the CAT-surfer maintains the conformational flexibility needed for a biological response, whereas CAT-skier favors the dissociation of the tetramer subunits, involving the inactivation of the enzyme.

Covalently immobilized catalase on functionalized graphene: effect on the activity, immobilization efficiency, and tetramer stability

Davide Barreca
Primo
;
Giulia Neri;Angela Scala;Enza Fazio;Anna Piperno
Ultimo
2018-01-01

Abstract

Herein we describe, for the first time, the covalent immobilization of catalase (CAT) on functionalized graphene surfaces (G) exploiting the azlactone chemistry for the post-functionalization of graphene-based materials. The structure, morphology and chemical composition of catalase immobilized on graphene (CAT-G) have been investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). The biological responses such as catalytic activity, cellular uptake, internalization pathway, ability to protect lymphocytes from oxidative stress induced by H2O2 together with the unforeseen ability to increase the lifetime of the free catalase in solution have been deeply investigated. From our studies, it emerges that the behavior of CAT covalently linked to modified graphene depends on CAT/G ratio that affects the secondary structure and the tetramer stability of CAT. In order to support the experimental results, we have also investigated the behaviors of two appropriately designed model systems, named CAT-surfer and CAT-skier, by molecular dynamics calculations. These in silico results parallel the experimental ones demonstrating our hypothesis that the CAT-surfer maintains the conformational flexibility needed for a biological response, whereas CAT-skier favors the dissociation of the tetramer subunits, involving the inactivation of the enzyme.
2018
File in questo prodotto:
File Dimensione Formato  
46- Biomaterials Science 2018.pdf

solo utenti autorizzati

Descrizione: Biomaterials Science_2018
Tipologia: Versione Editoriale (PDF)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 2.28 MB
Formato Adobe PDF
2.28 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3130427
Citazioni
  • ???jsp.display-item.citation.pmc??? 5
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 26
social impact