Zambrano, Gerardo (2020) New "bio-inspired devices": synthetic peroxidases for chemical and biotechnological applications. [Tesi di dottorato]

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Tipologia del documento:	Tesi di dottorato
Lingua:	English
Titolo:	New "bio-inspired devices": synthetic peroxidases for chemical and biotechnological applications
Autori:	Autore Email Zambrano, Gerardo gerardo.zambrano@unina.it
Data:	13 Marzo 2020
Numero di pagine:	224
Istituzione:	Università degli Studi di Napoli Federico II
Dipartimento:	Scienze Chimiche
Dottorato:	Scienze chimiche
Ciclo di dottorato:	32
Coordinatore del Corso di dottorato:	nome email Lombardi, Angelina alombard@unina.it
Tutor:	nome email Pavone, Vincenzo [non definito] Maglio, Ornella [non definito]
Data:	13 Marzo 2020
Numero di pagine:	224
Parole chiave:	peroxidases; heme protein models; biosensors; catalysis; nanomaterials
Settori scientifico-disciplinari del MIUR:	Area 03 - Scienze chimiche > CHIM/03 - Chimica generale e inorganica
Depositato il:	27 Mar 2020 11:59
Ultima modifica:	08 Nov 2021 12:16
URI:	http://www.fedoa.unina.it/id/eprint/13144

Abstract

Peroxidases are a large family of house–keeping enzymes expressed in all living kingdoms. These enzymes are involved in many life–sustaining processes that ensure homeostasis of intra– and extra–cellular environment. Among all, plant peroxidases are the most widely studied. They show common structural features such as a Fe3+–protoporphyrin IX (heme) as prosthetic group. In the enzyme resting state, the iron ion is invariantly penta–coordinated: four ligands are provided by the porphyrin ring, while a His residue is coordinated as the fifth axial ligand (namely, the proximal His). The sixth coordination position is occupied by solvent. From a catalytic point of view, peroxidases are peroxide–activated enzymes that couple H2O2 decomposition with oxidation of an organic (phenols, anilines, organic sulfides, etc.) or inorganic substrate (chloride ions, etc.). The great functional versatility makes peroxidases very attractive for practical applications in chemistry, biotechnology and medicine. Among all peroxidases, the peroxidase from horseradish (HRP) is one of the most used reporter enzyme in enzyme linked immunosorbent assays (ELISA), electrochemical and optical biosensors. The present PhD project, granted by Avantech Group s.r.l., is aimed to find and develop possible applications for synthetic peroxidases designed by a miniaturization approach. To this purpose, Fe(III)–Mimochrome VI*a (FeMC6*a) was used. Previous experiments, carried out on this synthetic peroxidase, demonstrated its higher performances under optimal conditions, compared to those of natural HRP, particularly in ABTS (a common chromogenic substrate used for peroxidases) oxidation. The synthetic FeMC6*a is provided with high catalytic versatility and enhanced performances despite its miniaturized scaffold (3.5 kDa), which encouraged investigations for many practical applications. In this project, FeMC6*a was successfully investigated in the fields of: i) bioremediation (chapter 2); ii) sensing (chapter 3); iii) bionanomaterials construction (chapter 4). i) FeMC6*a proved to be an efficient catalyst in the transformation of several halophenols, and the catalytic characterization using 2,4,6–trichlorophenol as model substrate confirmed its remarkable activity in oxidative dehalogenation reactions. This function was used to lay the basis for a new bioremediation strategy based on synthetic peroxidases. in which FeMC6*a was able to deplete 2,4,6–trichlorophenol from solution in nanomolar catalyst concentrations. ii) FeMC6*a was efficiently entrapped onto glassy carbon electrodes and the peculiarity of its redox behavior was exploited for the development of a synthetic peroxidase based halogenated alcohol sensor, in collaboration with Prof. Wing Cheung Mak from Linköping University. The sensing principle relies on the increase of catalytic currents upon addition of halogenated solvents. iii) FeMC6*a was immobilized onto gold nanoparticles and the catalytic performances of the obtained nano–bioconjugate were evaluated. The immobilization was achieved by means of a bio–orthogonal approach

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