Enantioselective Sulfoxidation Mediated by Vanadium-Incorporated Phytase: A Hydrolase Acting as a Peroxidase
Chem. Commun. 1998, 1891-1892, 10.1039/a804702b
Phytase (E.C. 18.104.22.168), which in vivo mediates the hydrolysis of phosphate esters, catalyses the enantioselective oxidation of thioanisole with H2O2, both in the presence and absence of vanadate ion, affording the S-sulfoxide in up to 66% ee at 100% conversion.
Ligand type: UndefinedOptimization: ---Max TON: ~194ee: 66PDB: ---Notes: ---
Max TON: 550ee: 66PDB: ---Notes: ---
Metal Substitution in Thermolysin: Catalytic Properties of Tungstate Thermolysin in Sulfoxidation with H2O2
Can. J. Chem. 2002, 80, 622-625, 10.1139/v02-082
The catalytic Zn2+ ion was extracted from thermolysin, which had been covalently bound to Eupergit C. The apo-enzyme incorporated the oxometallate anions MoO42, SeO42, and WO42 with partial restoration of the proteolytic activity. Tungstate thermolysin was moderately active in the sulfoxidation of thioanisole by hydrogen peroxide, whereas its activity towards phenylmercaptoacetophenone, which was designed to bind well in the active site of thermolysin, was much higher.
Metal: WLigand type: Amino acidHost protein: ThermolysinAnchoring strategy: Metal substitutionMax TON: ---ee: ---PDB: ---Notes: ---
The Rational Design of Semisynthetic Peroxidases
Biotechnol. Bioeng. 2000, 67, 87-96, 10.1002/(SICI)1097-0290(20000105)67:1<87::AID-BIT10>3.0.CO;2-8
A semisynthetic peroxidase was designed by exploiting the structural similarity of the active sites of vanadium dependent haloperoxidases and acid phosphatases. Incorporation of vanadate ion into the active site of phytase (E.C. 22.214.171.124), which mediates in vivo the hydrolysis of phosphate esters, leads to the formation of a semisynthetic peroxidase, which catalyzes the enantioselective oxidation of prochiral sulfides with H2O2 affording the S‐sulfoxide, e.g. in 66% ee at 100% conversion for thioanisole. Under reaction conditions the semi‐synthetic vanadium peroxidase is stable for over 3 days with only a slight decrease in turnover frequency. Polar water‐miscible cosolvents, such as methanol, dioxane, and dimethoxyethane, can be used in concentrations of 30% (v/v) at a small penalty in activity and enantioselectivity. Among the transition metal oxoanions that are known to be potent inhibitors, only vanadate resulted in a semisynthetic peroxidase when incorporated into phytase. A number of other acid phosphatases and hydrolases were tested for peroxidase activity, when incorporated with vanadate ion. Phytases from Aspergillus ficuum, A. fumigatus, and A. nidulans, sulfatase from Helix pomatia, and phospholipase D from cabbage catalyzed enantioselective oxygen transfer reactions when incorporated with vanadium. However, phytase from A. ficuum was unique in also catalyzing the enantioselective sulfoxidation, albeit at a lower rate, in the absence of vanadate ion.
Vanadium-Catalysed Enantioselective Sulfoxidations: Rational Design of Biocatalytic and Biomimetic Systems
Top. Catal. 2000, 13, 259-265, 10.1023/A:1009094619249
Approaches to the rational design of vanadium-based biocatalytic and biomimetic model systems as catalysts for enantioselective oxidations are reviewed. Incorporation of vanadate ion into the active site of phytase (E.C. 126.96.36.199), which in vivo mediates the hydrolysis of phosphate esters, afforded a relatively stable and inexpensive semi-synthetic peroxidase. It catalysed the enantioselective oxidation of prochiral sulfides with H2O2 affording the S-sulfoxide, e.g., in 68% ee at 100% conversion for thioanisole. Amongst the transition metal oxoanions that are known to be potent inhibitors of phosphatases, only vanadate resulted in a semi-synthetic peroxidase, when incorporated into phytase. In a biomimetic approach, vanadium complexes of chiral Schiff's base complexes were encapsulated in the super cages of a hydrophobic zeolite Y. Unfortunately, these ship-in-a-bottle complexes afforded only racemic sulfoxide in the catalytic oxidation of thioanisole with H2O2.