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Akita, Masaru; Tsutsumi, Daisuke; Kobayashi, Masami; Kise, Hideo

doi:10.1023/a:1012754624105

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…So, in the case of phenol oxidation by peroxidases, the nature of the produced polyphenol was shown to be largely affected by the nature of the organic cosolvent [15,49]. There have also been a number of reports on using ELISAbased systems (based on electrochemical detection and HRP as an enzyme label) for the detection of hydrophobic herbicides such as 2,4-dichlorophenoxyacetic acid [50,51].…”

Section: Bioelectrocatalytic Function Of Peroxidases In Waterrestrictmentioning

confidence: 99%

Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media

et al. 2005

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The bioelectrocatalytic function of two plant peroxidases, horseradish peroxidase (HRP) and a newly purified royal palm tree-leaf peroxidase (RPTP), was studied on graphite electrodes in aqueous buffer solutions, over the pH range 7.0 -3.0, and in aqueous buffer solutions, at pH 6.0, containing different amounts of a polar organic cosolvent, i.e., ethanol and acetonitrile. The kinetics of direct and of mediated (using catechol as mediator) reduction of H 2 O 2 at the HRP-and RPTP-modified graphite electrodes were analyzed amperometrically at À 50 mV(vs. Ag j AgCl j 0.1 M KCl) in a flow-through wall-jet electrochemical system. Values of the apparent rate constant of the heterogeneous electron transfer between the enzyme and graphite, k s , the rate constant for enzymatic reduction of H 2 O 2 , k 1 , and the rate constant of mediated reduction of H 2 O 2 , k 3, were determined using the modified Koutecky-Levich approach. Analysis of the variation of the rate constants and the response of the peroxidase-modified electrodes to H 2 O 2 with pH and content of the organic cosolvent demonstrated that maximal peroxidase bioelectrocatalytic activity occurred at pH 5.0 -6.0 and at concentrations of ethanol of 10 -20% v/v. At a lower pH, higher concentrations of ethanol, and in aqueous solutions of acetonitrile, the bioelectrocatalytic activity of the peroxidase-modified electrodes drastically decreased. However, contrary to the data for homogeneous catalysis, both peroxidases were bioelectrocatalytically active even in 95% organic co-solvents, thus demonstrating a stabilizing effect of the enzyme immobilization on the bioelectrocatalytic performance of the peroxidases. RPTP immobilized on graphite demonstrated lower overall activity but a higher pH-and organic cosolvent-stability than HRP.

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Section: Bioelectrocatalytic Function Of Peroxidases In Waterrestrictmentioning

confidence: 99%

Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media

et al. 2005

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“…Among the iron containing metalloporphyrins, hemin has been shown to be catalyze the oxidative polymerization of phenols. 10 Nevertheless, the catalytic activity is still low. 11 Hemin has been modified by attaching pendant groups such as b-cyclodextrin.…”

Section: Introductionmentioning

confidence: 99%

A stable biomimetic redoxcatalyst obtained by the enzyme catalyzed amidation of iron porphyrin

Nagarajan

Bruno

et al. 2009

Green Chem.

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Hematin, a hydroxyferriprotoporphyrin, is the more stable oxidized form of the free heme. The use of hematin as a catalyst for oxidative polymerization reactions has been restricted due to its limited aqueous solubility at low pH conditions. While there have been reports on the functionalization of hematin with poly (ethylene glycol), the esters formed are not very stable at low pH conditions. We report here the design and synthesis of hematin tethered with methoxypolyethylene glycol amine chains as a novel stable biomimetic catalyst. This one step amidation was performed under solventless conditions and catalyzed by a hydrolase (Novozyme-435). The amidation greatly improved the stability of hematin at low pH. Further, this catalyst was soluble in water and was able to catalyze the polymerization of aniline based monomers. The amide functionalized hematin serves as a robust cost-effective alternative to HRP, active even at lower pH conditions.

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Iron Catalysis in Biological and Biomimetic Reactions

Müller

Bröring

2008

Iron Catalysis in Organic Chemistry

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Untitled

Cited by 9 publications

References 10 publications

Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media

Bioelectrocatalysis of Plant Peroxidases Immobilized on Graphite in Aqueous and Mixed Solvent Media

A stable biomimetic redoxcatalyst obtained by the enzyme catalyzed amidation of iron porphyrin

Iron Catalysis in Biological and Biomimetic Reactions

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