1 Introduction
In the present context of worldwide consciousness regarding the necessity to preserve our habitat, it is now obvious that any human activity has to take into
consideration its impact on the environment. This is particularly true for the
chemical industry, which is at the origin of most manufactured products, and
therefore withstands a huge part of the responsibility for tomorrow’s wellness of the
planet. After about two centuries of prosperity and wild enterprise, the chemical
industry is now facing the daunting challenge to rethink most of its well-proven
processes and promote the development of environmentally friendly new ones
meeting standards for sustainable growth. While chemists still struggle to meet
these standards, nature has already solved the problem by evolving natural
enzymes, including metalloenzymes, which are capable of performing efficient
catalytic processes using harmless reactants under mild conditions. Such biocatalysts can indeed perform selective reactions in aqueous medium at ambient temperature and under atmospheric pressure. Yet, the use of natural enzymes in
biocatalytic processes shows some limitations such as thermal instability, substrate
specificity, or restriction to natural reactions. Evolving these natural enzymes by
replacing the original cofactor with a synthetic catalyst or simply inserting an
artificial metal complex into a protein scaffold by covalent or supramolecular
(“Trojan Horse”) anchoring affords a new class of catalysts that ideally combine the
robustness and wide range of reactions achieved by chemical catalysts with the
ability of enzymes to work under mild conditions, in aqueous medium, and with
high selectivity. Insertion of a synthetic metal complex into a protein gives rise to
so-called artificial metalloenzymes (ArMs) that eventually catalyze both natural and
non-natural reactions under eco-compatible conditions. The selectivity, the efficiency, and the stability of these ArMs can then be optimized by chemical engineering of the metal complex and/or biochemical engineering of the protein
scaffold, notably using the powerful technique of directed evolution. The present
chapter gives an overview of the wide range of reactions catalyzed by ArMs but
also goes beyond by describing how ArMs can be involved in cascade reaction
processes, as well as in in vivo catalysis for both natural and abiotic reactions.
2 Biotechnological Applications of Artificial
Metalloenzymes
Biotechnological applications of ArMs are potentially endless since the obvious
long-term objective is to replace all the contemporary polluting and
energy-consuming chemical processes by environmentally friendly new ones. This
sub-chapter surveys the variety of reactions that have successfully been catalyzed
by ArMs so far at the laboratory level, covering both the fields of oxidation and
reduction reactions as well as polymerization reactions.
Current Applications of Artificial Metalloenzymes …
365
In the present context of worldwide consciousness regarding the necessity to preserve our habitat, it is now obvious that any human activity has to take into
consideration its impact on the environment. This is particularly true for the
chemical industry, which is at the origin of most manufactured products, and
therefore withstands a huge part of the responsibility for tomorrow’s wellness of the
planet. After about two centuries of prosperity and wild enterprise, the chemical
industry is now facing the daunting challenge to rethink most of its well-proven
processes and promote the development of environmentally friendly new ones
meeting standards for sustainable growth. While chemists still struggle to meet
these standards, nature has already solved the problem by evolving natural
enzymes, including metalloenzymes, which are capable of performing efficient
catalytic processes using harmless reactants under mild conditions. Such biocatalysts can indeed perform selective reactions in aqueous medium at ambient temperature and under atmospheric pressure. Yet, the use of natural enzymes in
biocatalytic processes shows some limitations such as thermal instability, substrate
specificity, or restriction to natural reactions. Evolving these natural enzymes by
replacing the original cofactor with a synthetic catalyst or simply inserting an
artificial metal complex into a protein scaffold by covalent or supramolecular
(“Trojan Horse”) anchoring affords a new class of catalysts that ideally combine the
robustness and wide range of reactions achieved by chemical catalysts with the
ability of enzymes to work under mild conditions, in aqueous medium, and with
high selectivity. Insertion of a synthetic metal complex into a protein gives rise to
so-called artificial metalloenzymes (ArMs) that eventually catalyze both natural and
non-natural reactions under eco-compatible conditions. The selectivity, the efficiency, and the stability of these ArMs can then be optimized by chemical engineering of the metal complex and/or biochemical engineering of the protein
scaffold, notably using the powerful technique of directed evolution. The present
chapter gives an overview of the wide range of reactions catalyzed by ArMs but
also goes beyond by describing how ArMs can be involved in cascade reaction
processes, as well as in in vivo catalysis for both natural and abiotic reactions.
2 Biotechnological Applications of Artificial
Metalloenzymes
Biotechnological applications of ArMs are potentially endless since the obvious
long-term objective is to replace all the contemporary polluting and
energy-consuming chemical processes by environmentally friendly new ones. This
sub-chapter surveys the variety of reactions that have successfully been catalyzed
by ArMs so far at the laboratory level, covering both the fields of oxidation and
reduction reactions as well as polymerization reactions.
Current Applications of Artificial Metalloenzymes …
365