Chloroperoxidases

Styrene was successfully oxidized to the S-product both by xylene monooxygenase from P. putida mt-2 [113] and styrene monooxygenase from Pseudomonas sp.VLB120 [114] (Scheme 9.13), with the latter enzyme displaying a particularly large substrate tolerance with excellent stereoselectivity (>99% ee). In this context it is interesting to note that both xylene monooxygenase as well as chloroperoxidase are very selective for mono-epoxidation in case of presence of multiple alkene functionalities [115]. 

The alkane hydroxylase from Pseudomonas oleovorans is particularly suitable for the epoxidation of terminal aliphatic double bonds and enables rapid access to the (3-blocker metoprolol (Scheme 9.14) [113,116]. Complementing this regioselectivity, chloroperoxidases are particularly suitable biocatalysts for the epoxidation of (ds substituted) subterminal olefins [112,117]. This enzyme also accepts terminal olefins and is utilized for the effident synthesis of P-mevalono-ladone [118]. 

Heme-dependent haloperoxidases generate HOX as reactive species from H2O2 and X, which represents an X+ equivalent capable of undergoing electrophilic addition at electron-rich centers [270,271]. Aprototype biocatalyst of this group is the chloroperoxidase from Caldariomyces Jumago [272]. In many natural systems, such enzymes are responsible for the halogenation of electron-rich aromatic cores. 

Chloroperoxidase activity has also beeu fouud amoug degradative euzymes ... 

Chen YP, DE Lincol, SA Woodin, CR Lovell (1991) Purification and properties of a unique flavin-containing chloroperoxidase from the capitellid polychaete Notomastus lobatus. J Biol Chem 266 23909-23915. 

Libby RD, JA Thomas, LW Kaiser, LP Hager (1982) Chloroperoxidase halogenation reactions. J Biol Chem 257 5030-5037. 

Morris DR, LP Hager (1966) Chloroperoxidase 1 Isolation and properties of the crystalline protein. J Biol Chem 241 1763-1768. 

Simons BH, P Barnett, EGM Vollenbroek, HL Dekker, AO Muijsers, A Messerschmidt, R Wever (1995) Primary structure and characterization of the vanadium chloroperoxidase from the fungus Curvularia inaequalis. Eur J Biochem 229 566-574. 

Wiesner W, K-H van Pee, F Lingens (1988) Purification and characterization of a novel non-heme chloroperoxidase from Pseudomonas pyrrocinia. J Biol Chem 263 13725-13732. 

Renirie R, W Hemrika, R Wever (2000) Peroxidase and phosphatase activity of active-site mutants of vanadium chloroperoxidase from the fungus Curvularia inaequalis. J Biol Chem 275 11650-11657. 

A fairly sensitive ( 10 A/) homogeneous ECIA technique for human IgG using chloroperoxidase catalyzed COj production and subsequent potentiometric detection has recently been reported A more complex scheme using enzymes and amperometric determination of H2O2 has demonstrated micromolar sensitivity... 

The one-pot conversions of oximes to gem-halonitro compounds have been achieved by using A(/V,/V.-trihalo-l,3,5-triazines,131 chloroperoxidase in the presence of hydrogen peroxide and potassium chloride,132 or commercial OXONE and sodium chloride.133 Of these methods, the case of OXONE may be the most convenient (Eq. 2.65). 

Fedorak, P. M. Semple, K. M. Vazquez-Duhalt, R., and Westlake, D. W. S., Chloroperoxidase-mediated modifications of petroporphyrins and asphaltenes. Enzyme Microb Technol, 1993. 15 pp. 429-437. 

Vazquez-Duhalt, R. Ayala, M., and Marquez-Rocha, F. J., Biocatalytic chlorination of aromatic hydrocarbons by chloroperoxidase of Caldariomyces fumago. Phytochemisty, 2001. 58 pp. 929-933. 

Ayala, M. Robledo, N. R. Lopez-Munguia, A., and Vazquez-Duhalt, R., Substrate specificity and ionization potential in chloroperoxidase-catalyzed oxidation of diesel fuel. Environmental Science Technology, 2000. 34(13) pp. 2804-2809. 

In this work, we have grafted the mesoporous SBA-15 materials with 3-aminopropyl trimethoxysilane [10], In a subsequent step, the aminopropyl moiety was reacted with glutardialdehyde, which reacts also with amino groups of the enzymes chloroperoxidase (CPO) and glucose oxidase (GOx) (Scheme 1). 

Taurog et al. [216] showed that contrary to previous suggestions, both iodination and coupling are catalyzed by the oxoferryl porphyrin Tr-cation radical of TPO Compound I and not the oxoferryl protein radical. HRP catalyzed the oxidation of bisulfite to sulfate with the intermediate formation of sulfur trioxide radical anion S03 [217] HPO, MPO, LPO, chloroperoxidase, NADH peroxidase, and methemoglobin oxidized cyanide to cyanyl radical [218],... 

Scheme 24 Reactions and conditions i) Chloroperoxidase from Caldariomyces fumago, H2O2, halide ion, H20.

Chloropentakis(ethanol) cobaltCII), thermochromic material, 6 615 Chloroperoxidases, as bleaching agents, 4 66-67... 

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