Kinetic and molecular orbital studies on the rate of oxidation of monosubstituted phenols and anilines by horseradish peroxidase compound II

Biochemistry ◽  
1990 ◽  
Vol 29 (17) ◽  
pp. 4093-4098 ◽  
Author(s):  
Junji Sakurada ◽  
Reiko Sekiguchi ◽  
Koichi Sato ◽  
Toichiro Hosoya
Keyword(s):  
Horseradish Peroxidase ◽  
Molecular Orbital ◽  
Compound Ii

Kinetic studies on the oxidation of phenols by the horseradish peroxidase compound II

1997 ◽  
Vol 1339 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Prasanta K. Patel ◽  
Madhu Sudan Mondal ◽  
Sandeep Modi ◽  
Digambar V. Behere
Keyword(s):  
Horseradish Peroxidase ◽  
Kinetic Studies ◽  
Oxidation Of Phenols ◽  
Compound Ii

Rate constants for reactions of horseradish peroxidase compounds I and II with 4-substituted arylboronic acids

1994 ◽  
Vol 72 (10) ◽  
pp. 2159-2162 ◽  
Author(s):  
Weimei Sun ◽  
Xiaoying Ji ◽  
Larry J. Kricka ◽  
H. Brian Dunford
Keyword(s):  
Horseradish Peroxidase ◽  
Rate Constants ◽  
Compound I ◽  
Arylboronic Acid ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Arylboronic Acids ◽  
Total Ionic Strength ◽  
Compound Ii ◽  
Catalyzed Oxidation

The rate constants for the reactions of horseradish peroxidase compound I (k1) and compound II (k2) with three 4-substituted arylboronic acids, which enhance chemiluminescence in the horseradish peroxidase catalyzed oxidation of luminol by hydrogen peroxide, were determined at pH 8.6, total ionic strength 0.11 M, using stopped-flow kinetic measurements. For comparison, the rate constants of the reactions of 4-iodophenol with compounds I and II were also determined under the same experimental conditions. The three arylboronic acid derivatives and their rate constants are: 4-biphenylboronic acid, k1 = (1.21 ± 0.08) × 106 M−1 s−1, k2 = (4.6 ± 0.2) × 105 M−1 s−1; 4-bromophenylboronic acid, k1 = (5.5 ± 0.2) × 104 M−1 s−1, k2 = (3.6 ± 0.2) × 104 M−1 s−1; and 4-iodophenylboronic acid, k1 = (1.1 ± 0.2) × 105 M−1 s−1, k2 = (1.3 ± 0.1) × 104 M−1 s−1. 4-Biphenylboronic acid, which shows comparable luminescent enhancement to 4-iodophenol, has the highest reactivity in the reduction of both compounds I and II among the three arylboronic acid derivatives tested.

Studies on Horseradish Peroxidase. VII. A Kinetic Study of the Oxidation of Iodide by Horseradish Peroxidase Compound II

1971 ◽  
Vol 49 (18) ◽  
pp. 3059-3063 ◽  
Author(s):  
R. Roman ◽  
H. B. Dunford ◽  
M. Evett
Keyword(s):  
Ionic Strength ◽  
Horseradish Peroxidase ◽  
Kinetic Study ◽  
Rate Constant ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
Acid Dissociation ◽  
Ph Range ◽  
Compound Ii ◽  
Kinetics Of

The kinetics of the oxidation of iodide ion by horseradish peroxidase compound II have been studied as a function of pH at 25° and ionic strength of 0.11. The logarithm of the second-order rate constant decreases linearly from 2.3 × 105 to 0.1 M−1 s−1 with increasing pH over the pH range 2.7 to 9.0. The pH dependence of the reaction is explained in terms of an acid dissociation outside the pH range of the study.

scholarly journals Scavenging of oxygen radicals by heme peroxidases.

1996 ◽  
Vol 43 (4) ◽  
pp. 673-678 ◽  
Author(s):  
L Gebicka ◽  
J L Gebicki
Keyword(s):  
Horseradish Peroxidase ◽  
Hydroxyl Radicals ◽  
Superoxide Radical ◽  
Cation Radical ◽  
Compound I ◽  
Superoxide Radical Anion ◽  
Form Compound ◽  
Activity Loss ◽  
Heme Peroxidases ◽  
Compound Ii

The reactions of two heme peroxidases, horseradish peroxidase and lactoperoxidase and their compounds II (oxoferryl heme intermediates, Fe(IV) = O or ferric protein radical Fe(III)R.) and compounds III (resonance hybrids [Fe(III)-O2-. Fe(II)-O2] with superoxide radical anion generated enzymatically or radiolytically, and with hydroxyl radicals generated radiolytically, were investigated. It is suggested that only the protein radical form of compound II of lactoperoxidase reacts with superoxide, whereas compound II of horseradish peroxidase, which exists only in oxoferryl form, is unreactive towards superoxide. Compound III of the investigated peroxidases does not react with superoxide. The lactoperoxidase activity loss induced by hydroxyl radicals is closely related to the loss of the ability to form compound I (oxoferryl porphyrin pi-cation radical, Fe(IV) = O(Por+.) or oxoferryl protein radical Fe(IV) = O(R.)). On the other hand, the modification of horseradish peroxidase induced by hydroxyl radicals has been reported to cause also restrictions in substrate binding (Gebicka, L. & Gebicki, J.L., 1996, Biochimie 78, 62-65). Nevertheless, it has been found that only a small fraction of hydroxyl radicals generated homogeneously does inactivate the enzymes.

Activation volumes for horseradish peroxidase compound ii reactions

1982 ◽  
Vol 15 (1) ◽  
pp. 15-18 ◽  
Author(s):  
Isobel M. Ralston ◽  
Jan Wauters ◽  
Karel Heremans ◽  
H. Brian Dunford
Keyword(s):  
Horseradish Peroxidase ◽  
Compound Ii

scholarly journals Influence of cellobiose oxidase on peroxidases from Phanerochaete chrysosporium

1993 ◽  
Vol 293 (2) ◽  
pp. 431-435 ◽  
Author(s):  
P Ander ◽  
G Sena-Martins ◽  
J C Duarte
Keyword(s):  
Cytochrome C ◽  
Horseradish Peroxidase ◽  
Phanerochaete Chrysosporium ◽  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Veratryl Alcohol ◽  
Lag Phase ◽  
And Function ◽  
Compound Ii ◽  
Catalytic Cycles

Reduction of H2O2-oxidized manganese peroxidase (MnP), lignin peroxidase and, to some extent, horseradish peroxidase, was studied in the presence of cellobiose oxidase (CbO) and cellobiose. It was found that the reversion rates for MnP compound II and lignin peroxidase compound II back to native enzymes increased significantly in the presence of CbO and cellobiose. However, the reduction of cytochrome c by CbO plus cellobiose was 40 times faster than the reduction of MnP compound II. Also, the lag phase before reversion to the native states decreased for all three peroxidases in the presence of CbO and cellobiose. Active CbO did not repress formation of compounds I or II of the peroxidases, and Mn2+/veratryl alcohol reduced compound II of the peroxidases much more rapidly than did active CbO. This indicates that, in the presence of Mn2+ or veratryl alcohol, MnP and lignin peroxidase can complete their catalytic cycles and function normally without interference from CbO. Without the presence of peroxidase substrates, active CbO reduced compound II of the above peroxidases.

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