Trasformazioni Chimiche Fotoenzimatiche Mediate da (Co)Polimeri Strutturati a Livello Molecolare

ABSTRACT THESIS Enzyme catalysis and photocatalysis have emerged as powerful and complementary tools in modern organic synthesis, offering a sustainable alternative to conventional chemical transformations. Through the use of enzymes or photoactive molecules, reactions that would otherwise require harsh conditions can be achieved efficiently under mild conditions. Among the enzymes employed in biocatalysis, old yellow enzymes (OYEs) have emerged as promising platforms for challenging chemical transformations, such as the reduction of activated carbon–carbon double bonds. However, a major limitation of these enzymatic processes is the reliance on natural nicotinamide cofactors, such as NAD(P)H, which are costly, poorly stable, and often required in stoichiometric amounts. These drawbacks significantly limit the practical and industrial application of enzymatic systems. To address these limitations, photobiocatalysis has emerged as a more sustainable alternative, in which photoactive molecules can replace natural cofactors upon activation with visible light. This thesis aims to provide a preliminary investigation into the fabrication of a polymer–protein conjugate in which an old yellow enzyme homologue, YqjM, is covalently linked to a polymer bearing photoactive moieties, with the goal of developing a novel cofactor-independent enzymatic system. Specifically, the first part of this work focused on the synthesis and characterization of two eosin Y (EY)-based photoactive monomers. In the second part, reversible addition–fragmentation chain-transfer (RAFT) polymerization, a controlled radical polymerization technique, was employed to synthesize polymers with controlled molecular weight and tunable composition, particularly with respect to photocatalyst loading. Finally, the interactions between the copolymers and the protein, as well as their photoenzymatic performance in the reduction of methylcycohexenone to methylcyclohexanone, were investigated.