An Artificial Enzyme Made by Covalent Grafting of an FeII Complex into β-Lactoglobulin: Molecular Chemistry, Oxidation Catalysis, and Reaction-Intermediate Monitoring in a Protein
Chem. - Eur. J. 2015, 21, 12188-12193, 10.1002/chem.201501755
An artificial metalloenzyme based on the covalent grafting of a nonheme FeII polyazadentate complex into bovine β‐lactoglobulin has been prepared and characterized by using various spectroscopic techniques. Attachment of the FeII catalyst to the protein scaffold is shown to occur specifically at Cys121. In addition, spectrophotometric titration with cyanide ions based on the spin‐state conversion of the initial high spin (S=2) FeII complex into a low spin (S=0) one allows qualitative and quantitative characterization of the metal center’s first coordination sphere. This biohybrid catalyst activates hydrogen peroxide to oxidize thioanisole into phenylmethylsulfoxide as the sole product with an enantiomeric excess of up to 20 %. Investigation of the reaction between the biohybrid system and H2O2 reveals the generation of a high spin (S=5/2) FeIII(η2‐O2) intermediate, which is proposed to be responsible for the catalytic sulfoxidation of the substrate.
Metal: FeLigand type: Poly-pyridineAnchoring strategy: CovalentOptimization: ---Reaction: SulfoxidationMax TON: 5.6ee: 20PDB: ---Notes: ---
Artificial Metalloenzymes Derived from Bovine β-Lactoglobulin for the Asymmetric Transfer Hydrogenation of an Aryl Ketone – Synthesis, Characterization and Catalytic Activity
Dalton Trans. 2014, 43, 5482-5489, 10.1039/c3dt53253d
Protein hybrids resulting from the supramolecular anchoring to bovine β-lactoglobulin of fatty acid-derived Rh(iii) diimine complexes catalysed the asymmetric transfer hydrogenation of trifluoroacetophenone with up to 32% ee.
Metal: RhLigand type: Cp*; Poly-pyridineAnchoring strategy: SupramolecularOptimization: ChemicalReaction: HydrogenationMax TON: 14ee: 32PDB: ---Notes: ---
Enantioselective Transfer Hydrogenation of Ketone Catalysed by Artificial Metalloenzymes Derived from Bovine β-Lactoglobulin
Chem. Commun. 2012, 48, 11984, 10.1039/c2cc36980j
Artificial metalloproteins resulting from the embedding of half-sandwich Ru(II)/Rh(III) fatty acid derivatives within β-lactoglobulin catalysed the asymmetric transfer hydrogenation of trifluoroacetophenone with modest to good conversions and fair ee's.
Metal: RhLigand type: Cp*; Poly-pyridineAnchoring strategy: SupramolecularOptimization: ChemicalReaction: HydrogenationMax TON: 34ee: 26PDB: ---Notes: ---