Bridging Oxidase- and Oxygen Reduction Electro-Catalysis by Model Single-Atom Catalysts

Nanocatalysts with enzyme-like catalytic activities, such as oxidase-mimics, are extensively used in biomedicine and environmental treatment. Searching enzyme-like nanomaterials, clarifying the origins of catalytic activity and developing <a></a><a>activity assessment</a> methodologies are therefore of great significance. Here we report that the oxidase- and oxygen reduction reaction (ORR) electro-catalysis can be well-bridged based on their identical activity origins, which makes the facile electrocatalytic ORR activity measurements intrinsically applicable to the oxidase-like activity evaluations. Inspired by natural heme-copper oxidases, Cu/Fe doped <a>single-atom </a><a>catalysts</a> (SACs) were first synthesized and used as model <a>catalysts</a>. Chromogenic reactions, electrochemical voltammetric measurements and <a></a><a>density functional theory</a> calculations further verify <a>the </a>linear relationship between their oxidase-like and ORR catalytic activities of the catalysts, thus an effective descriptor () are proposed for the rapid enzymic catalyst evaluation. <a>The enhanced tumour therapeutic efficacy</a> of SACs has been evidenced to result from their oxidase-like/ORR activities, which prove that numerous ORR electrocatalysts are promising candidates for oxidase mimics and tumour therapy. The synergistic catalytic effect of the biomimetic hetero-binuclear Cu-Fe centres has also been probed thoroughly.

Bridging Oxidase- and Oxygen Reduction Electro-Catalysis by Model Single-Atom Catalysts

Nanocatalysts with enzyme-like catalytic activities, such as oxidase-mimics, are extensively used in biomedicine and environmental treatment. Searching enzyme-like nanomaterials, clarifying the origins of catalytic activity and developing <a></a><a>activity assessment</a> methodologies are therefore of great significance. Here we report that the oxidase- and oxygen reduction reaction (ORR) electro-catalysis can be well-bridged based on their identical activity origins, which makes the facile electrocatalytic ORR activity measurements intrinsically applicable to the oxidase-like activity evaluations. Inspired by natural heme-copper oxidases, Cu/Fe doped <a>single-atom </a><a>catalysts</a> (SACs) were first synthesized and used as model <a>catalysts</a>. Chromogenic reactions, electrochemical voltammetric measurements and <a></a><a>density functional theory</a> calculations further verify <a>the </a>linear relationship between their oxidase-like and ORR catalytic activities of the catalysts, thus an effective descriptor () are proposed for the rapid enzymic catalyst evaluation. <a>The enhanced tumour therapeutic efficacy</a> of SACs has been evidenced to result from their oxidase-like/ORR activities, which prove that numerous ORR electrocatalysts are promising candidates for oxidase mimics and tumour therapy. The synergistic catalytic effect of the biomimetic hetero-binuclear Cu-Fe centres has also been probed thoroughly.

Molecular understanding of heteronuclear active sites in heme–copper oxidases, nitric oxide reductases, and sulfite reductases through biomimetic modelling

Review surveying biomimetic modeling and molecular understanding of heteronuclear metalloenzyme active sites involved in dioxygen, nitric oxide, and sulfite reduction.

A common coupling mechanism for A-type heme-copper oxidases from bacteria to mitochondria

Mitochondria metabolize almost all the oxygen that we consume, reducing it to water by cytochrome c oxidase (CcO). CcO maximizes energy capture into the protonmotive force by pumping protons across the mitochondrial inner membrane. Forty years after the H+/e− stoichiometry was established, a consensus has yet to be reached on the route taken by pumped protons to traverse CcO’s hydrophobic core and on whether bacterial and mitochondrial CcOs operate via the same coupling mechanism. To resolve this, we exploited the unique amenability to mitochondrial DNA mutagenesis of the yeast Saccharomyces cerevisiae to introduce single point mutations in the hydrophilic pathways of CcO to test function. From adenosine diphosphate to oxygen ratio measurements on preparations of intact mitochondria, we definitely established that the D-channel, and not the H-channel, is the proton pump of the yeast mitochondrial enzyme, supporting an identical coupling mechanism in all forms of the enzyme.

Activation of O2 and NO in heme-copper oxidases – mechanistic insights from computational modelling

Recent computational studies elucidate the mechanisms in heme-copper oxidases for energy conservation and reduction of O2 and NO.

Biochemistry of Copper Site Assembly in Heme-Copper Oxidases: A Theme with Variations

Copper is an essential cofactor for aerobic respiration, since it is required as a redox cofactor in Cytochrome c Oxidase (COX). This ancient and highly conserved enzymatic complex from the family of heme-copper oxidase possesses two copper sites: CuA and CuB. Biosynthesis of the oxidase is a complex, stepwise process that requires a high number of assembly factors. In this review, we summarize the state-of-the-art in the assembly of COX, with special emphasis in the assembly of copper sites. Assembly of the CuA site is better understood, being at the same time highly variable among organisms. We also discuss the current challenges that prevent the full comprehension of the mechanisms of assembly and the pending issues in the field.