Chloroperoxidase catalyzed oxidations in t-butyl alcohol/water mixtures

Deurzen, M. P. J. van; Remkes, I.J.; Rantwijk, Fred van; Sheldon, Roger A.

doi:10.1016/s1381-1169(96)00259-2

Cited by 84 publications

(58 citation statements)

References 20 publications

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“…From a practical point of view however, it is not necessary to have pseudo first order conditions and indeed, it is economically undesirable to have a large excess of one reactant. 60 High substrate concentrations 17,42,67 or the slow addition of peroxide 13,14 can prevent the build-up of excess peroxide which ultimately leads to deactivation indicating that the optimal system involves the addition of peroxide at the rate at which it is consumed 40 . Therefore it should be possible to minimise the effect 65 of solvent-aided deactivation by careful consideration of the reaction conditions.…”

Section: Discussionmentioning

confidence: 99%

“…These features are consistent with the formation of a 6-coordinate, low-spin haem species 56 which is likely to inhibit peroxide binding to the MP-11 and lower the catalytic activity. For 5% THF, a red- 40 shift in peak position and significant reduction in intensity (80%) was noted for the Soret band. Almost all other spectral features disappeared.…”

Section: Kinetics Of Sulphide Oxidationmentioning

confidence: 98%

“…The samples were diluted in mobile phase prior to injection (20 L). 40 Confirmation of the reaction product as methyl phenyl sulfoxide and that no sulfone was formed was carried out by extracting the reaction mixture in diethyl ether. The enantioselectivity of the reaction catalysed by MP-11 was determined in a similar manner.…”

Section: Hplc Analysismentioning

confidence: 99%

“…When taken in conjunction with the NAcMP-11 data, it leads to the conclusion that the decrease in activity observed at high alcohol concentrations can be attributed to the solvent competing with the peptide binding site for the hydrophobic substrate. 40 …”

Section: Effect Of Alcohols On Mp-11 Activitymentioning

confidence: 99%

“…Microperoxidases (MPs) are the products of the proteolytic 35 digestion of cytochrome c. MP-11 contains residues 11 -21 of the parent protein and is prepared by the action of pepsin on cytochrome c. The haem group is covalently attached to the Cys14 and Cys17 residues via sulfide bonds and is coordinated on the proximal side by the imidazole nitrogen of His18. The 6th axial 40 ligand position is either unoccupied or loosely coordinated by water 18 . In this respect the haem configuration is analogous to that of the peroxidase enzymes and MP-11 displays typical peroxidase activity.…”

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confidence: 99%

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The effect of solvent on the catalytic properties of microperoxidase-11

O’Reilly

Magner

2011

Phys. Chem. Chem. Phys.

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The effect of a range of solvents on the catalytic oxidation of methyl phenyl sulfide to methyl phenyl sulfoxide by MP-11 and by a cyclodextrin derivative of MP-11 was examined. The addition of low concentrations of alcohols enhanced the initial rate of sulfoxidation rate, most likely due to dispersion of MP-11 aggregates. Higher alcohol concentrations resulted in a decrease in activity arising from solvation of the hydrophobic sulfide, disrupting binding to the catalyst. In alcohols 10 the yield of product was decreased arising from increased rates of MP-11 deactivation via the formation of aldehydes (for primary alcohols) or by peroxide deactivation. The catalytic activity of cyclodextrin modified MP-11 was similar to that of MP-11 itself, demonstrating that it is the Ntermianal side of MP-11 which is the determinant of catalytic activity. Introduction 15The function of enzymes and proteins in non-aqueous solvents has been well established and, in some cases, commercialised [1][2][3][4][5] . Enzyme catalysis and biosensing in organic solvents offers many advantages over aqueous-based processes including increased substrate/analyte solubility, enhanced thermal stability, more 20 favourable reaction thermodynamics, ease of product / biocatalyst recovery and modified selectivity 1,2,[6][7][8][9][10] . The peroxidases are an important group of enzymes which catalyse a wide variety of synthetically useful oxidation reactions using peroxides as oxidants. In spite of this, their potential in non-aqueous catalytic 25 systems has yet to be realised. This may, in part, be attributed to deactivation of the enzymes by the peroxide oxidant at the concentrations required for such reactions [10][11][12] . Strategies to overcome this problem have been developed, including the slow addition 13 or in-situ generation 14 of the peroxide. Alternatively, 30 studies have shown that a high concentration of substrate relative to the peroxide aids the regeneration of the native enzyme and prevents the formation of the peroxidase intermediates which result in enzyme deactivation [15][16][17] . Microperoxidases (MPs) are the products of the proteolytic 35 digestion of cytochrome c. MP-11 contains residues 11 -21 of the parent protein and is prepared by the action of pepsin on cytochrome c. The haem group is covalently attached to the Cys14 and Cys17 residues via sulfide bonds and is coordinated on the proximal side by the imidazole nitrogen of His18. The 6th axial 40 ligand position is either unoccupied or loosely coordinated by water 18 . In this respect the haem configuration is analogous to that of the peroxidase enzymes and MP-11 displays typical peroxidase activity.The array of reactions catalysed by MPs is extensive. The 45 oxidation of phenolic substrates 17,19,20 , peroxide decomposition 21 , sulfide oxidation 22 , Mn 2+ oxidation 23 , the nitration of phenol in the presence of NO 2 -24 , the oxidation of N-methylcarbazole 25 and the dehalogenation of halophenols 26 have all been reported. Thus MPs display activity similar not on...

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Section: Discussionmentioning

confidence: 99%

Section: Kinetics Of Sulphide Oxidationmentioning

confidence: 98%

Section: Hplc Analysismentioning

confidence: 99%

Section: Effect Of Alcohols On Mp-11 Activitymentioning

confidence: 99%

mentioning

confidence: 99%

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The effect of solvent on the catalytic properties of microperoxidase-11

O’Reilly

Magner

2011

Phys. Chem. Chem. Phys.

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The rational design of semisynthetic peroxidases

Velde

Könemann

Rantwijk

et al. 2000

Biotechnol. Bioeng.

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Selective Oxidation – Homogeneous

Sheldon

Brink

Arends

2002

Encyclopedia of Catalysis

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In the manufacture of fine chemicals there is a considerable pressure to replace traditional oxidation techniques, using stoichiometric quantities of high valent metal salts, with cleaner, catalytic alternatives. This article focuses on homogeneous catalysis of liquid‐phase oxidations employing dioxygen, hydrogen peroxide, or alkyl hydroperoxides as the primary oxidant. Where relevant, heterogeneous equivalents are also discussed. Following a general introduction, which includes a discussion of the different reaction mechanisms and of the design of ligands for oxidation catalysts, the different classes of substrates are discussed. These are alkenes (epoxidation, vicinal dihydroxylation, oxidative cleavage, ketonization, and allylic oxidation), alkanes and alkyl aromatics (side‐chain versus aromatic‐ring oxidation), oxygen‐containing compounds (alcohols, diols, aldehydes, ketones, phenols, and ethers), amines, and sulfur‐containing compounds. A separate section is devoted to asymmetric catalysis (epoxidation and dihydroxylation of olefins, sulfoxidation, and Baeyer–Villiger oxidation).

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Chloroperoxidase catalyzed oxidations in t-butyl alcohol/water mixtures

Cited by 84 publications

References 20 publications

The effect of solvent on the catalytic properties of microperoxidase-11

The effect of solvent on the catalytic properties of microperoxidase-11

The rational design of semisynthetic peroxidases

Selective Oxidation – Homogeneous

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