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This study investigates the site‐directed immobilization of a hybrid catalyst bearing a biquinoline‐based‐Pd(II) complex (1) and a robust laccase within cavities of a silica foam to favor veratryl alcohol oxidation. We performed the grafting of 1 at a unique surface located lysine of two laccase variants, either at closed (1⊂UNIK157) or opposite position (1⊂UNIK71) of the enzyme oxidation site. After immobilization into the cavities of silica monoliths bearing hierarchical porosity, we show that catalytic activity is dependent on the orientation and loading of each hybrid, 1⊂UNIK157 being twice as active than 1⊂UNIK71 (203 TON vs 100 TON) when operating under continuous flow. These systems can be reused 5 times, with an operational activity remaining as high as 40 %. We show that the synergy between 1 and laccase can be tuned within the foam. This work is a proof of concept for controlling the organization of a heterogeneous hybrid catalyst using a Pd/laccase/silica foam. [ABSTRACT FROM AUTHOR]

A maximization of a direct electron transfer (DET) between redox enzymes and electrodes can be obtained through the oriented immobilization of enzymes onto an electroactive surface. Here, a strategy for obtaining carbon nanotube (CNTs) based electrodes covalently modified with perfectly control‐oriented fungal laccases is presented. Modelizations of the laccase‐CNT interaction and of electron conduction pathways serve as a guide in choosing grafting positions. Homogeneous populations of alkyne‐modified laccases are obtained through the reductive amination of a unique surface‐accessible lysine residue selectively engineered near either one or the other of the two copper centers in enzyme variants. Immobilization of the site‐specific alkynated enzymes is achieved by copper‐catalyzed click reaction on azido‐modified CNTs. A highly efficient reduction of O2 at low overpotential and catalytic current densities over −3 mA cm−2 are obtained by minimizing the distance from the electrode surface to the trinuclear cluster. [ABSTRACT FROM AUTHOR]

Oxidation reactions are highly important chemical transformations that still require harsh reaction conditions and stoichiometric amounts of chemical oxidants that are often toxic. To circumvent these issues, olefins oxidation is achieved in mild conditions upon irradiation of an aqueous solution of the complex [Ru(bpy)3]2+ and the enzyme laccase. Epoxide formation is coupled to the light-driven reduction of O2 by [Ru(bpy)3]2+/laccase system. The reactivity can be explained by dioxygen acting both as an oxidative agent and as renewable electron acceptor, avoiding the use of a sacrificial electron acceptor. [ABSTRACT FROM AUTHOR]

A linear decapeptide containing three His and one Asp residues and a β-turn-inducing dProPro unit was synthesised. A detailed potentiometric, mass spectrometric and spectroscopic study showed that at a 1:1 ratio of CCu/Cpeptide this peptide formed a major [CuH(OdProAsp)]2+ species (pH range 5.5-7.0), in which the Cu2+ ion was bound to the His and Asp residues in square-planar or square-pyramidal geometries. The stability constant corrected for protonated species (log K* [ABSTRACT FROM AUTHOR]