Kinetics of the oxidation of p-aminobenzoic acid catalyzed by horseradish peroxidase compounds I and II.

Dunford, H. Brian; Cotton, M. L.

doi:10.1016/s0021-9258(19)41575-5

Cited by 46 publications

(8 citation statements)

References 23 publications

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“…At high concentrations of malonate (10 and 20 mM), the plots of k0bS versus Mn11 concentration are hyperbolic (Figure 4A). Nonlinear saturation responses have been observed previously for the reactions of MnP compounds I and II with Mn11 in lactate (Wariishi et al, 1989), for the reductions of horseradish peroxidase compounds I and II with p-cresol (Hewson & Dunford, 1976; Critchlow & Dunford, 1972) and p-aminobenzoic acid (Dunford & Cotton, 1975), and for the reduction of LiP compound II with veratryl alcohol (Wariishi et al, 1991a). This can be attributed to the binding interaction between the enzyme and substrate followed by enzyme reduction (eqs 1-3).…”

Section: Discussionmentioning

confidence: 56%

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Kishi¹,

Wariishi²,

Marquez³

et al. 1994

Biochemistry

122

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The effect of oxalate, malonate, lactate, and succinate chelators on the reduction of Phanerochaete chrysosporium manganese peroxidase compound II by MnII was investigated using stopped-flow techniques. All rate data were collected from single-turnover experiments under pseudo-first-order conditions. With oxalate, the reduction of compound II by MnII exhibited saturation behavior when the observed pseudo-first-order rate constants were plotted against oxalate concentration. The plots passed through the origin, indicating that the reduction by MnII is irreversible at all concentrations of oxalate. Maximal stimulation of the rate of compound II reduction occurred at 2 mM oxalate, the concentration of oxalate found in the extracellular medium of agitated cultures of this fungus. In contrast, maximal stimulation of the reduction of compound II by MnII only was observed at high (> 20 mM) nonphysiological concentrations of malonate and lactate. Furthermore, at low concentrations of malonate and lactate, the reduction of compound II appeared to be reversible. These results suggest that at physiological concentrations oxalate chelates and stabilizes MnIII, enhancing its efficient removal from the enzyme. The rate constants for compound II reduction exhibited bell-shaped curves as a function of pH and had optima at pHs 5.0-5.4. In the presence of succinate, triphasic kinetics were observed for compound II reduction by MnII. In contrast to the reduction of compound II by MnII, various chelators had no observable effect on the formation of compound I. However, they did affect the steady-state oxidation of 2,6-dimethoxyphenol.

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Section: Discussionmentioning

confidence: 56%

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Kishi¹,

Wariishi²,

Marquez³

et al. 1994

Biochemistry

122

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“…This suggests that resorcinol adopts a revised orientation with respect to the heme. It should be noted that the distance r is calculated from an observed average relaxation rate of H4 and H6, and this rate is proportional to the average of the (1/r) 6 for each proton. Therefore, the distance to H4/H6 determined by NMR should be considered that from the closest adjacent proton.…”

Section: Discussionmentioning

confidence: 99%

Binding of Salicylhydroxamic Acid and Several Aromatic Donor Molecules toArthromyces ramosusPeroxidase, Investigated by X-ray Crystallography, Optical Difference Spectroscopy, NMR Relaxation, Molecular Dynamics, and Kinetics^,

et al. 1999

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The X-ray crystal structure of the complex of salicylhydroxamic acid (SHA) with Arthromyces ramosus peroxidase (ARP) has been determined at 1.9 A resolution. The position of SHA in the active site of ARP is similar to that of the complex of benzhydroxamic acid (BHA) with ARP [Itakura, H., et al. (1997) FEBS Lett. 412, 107-110]. The aromatic ring of SHA binds to a hydrophobic region at the opening of the distal pocket, and the hydroxamic acid moiety forms hydrogen bonds with the His56, Arg52, and Pro154 residues but is not asscoiated with the heme iron. X-ray analyses of ARP-resorcinol and ARP-p-cresol complexes failed to identify the aromatic donor molecules, most likely due to the very low affinities of these aromatic donors for ARP. Therefore, we examined the locations of these and other aromatic donors on ARP by the molecular dynamics method and found that the benzene rings are trapped similarly by hydrophobic interactions with the Ala92, Pro156, Leu192, and Phe230 residues at the entrance of the heme pocket, but the dihedral angles between the benzene rings and the heme plane vary from donor to donor. The distances between the heme iron and protons of SHA and resorcinol are similar to those obtained by NMR relaxation. Although SHA and BHA are usually considered potent inhibitors for peroxidase, they were found to reduce compound I and compound II of ARP and horseradish peroxidase C in the same manner as p-cresol and resorcinol. The aforementioned spatial relationships of these aromatic donors to the heme iron in ARP are discussed with respect to the quantum chemical mechanism of electron transfer in peroxidase reactions.

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“…Proposing the formation of such a complex, on the basis of the kinetic studies, is not without precedent in the peroxidase field. Dunford and Cotton (1975) proposed, from kinetic analyses, that, during oxidation of p-aminobenzoic acid by horseradish peroxidase, the free radical product of one-electron oxidation of p-aminobenzoic acid by HRPI forms a complex with HRPII. The HRPII-free radical complex reacts slower with an additional molecule of p-aminobenzoic acid than the pure HRPII.…”

Section: Lip°0mentioning

confidence: 99%

Veratryl alcohol oxidation by lignin peroxidase

Khindaria¹,

Yamazaki²,

Aust³

1995

Biochemistry

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Kinetics of the oxidation of p-aminobenzoic acid catalyzed by horseradish peroxidase compounds I and II.

Cited by 46 publications

References 23 publications

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Binding of Salicylhydroxamic Acid and Several Aromatic Donor Molecules toArthromyces ramosusPeroxidase, Investigated by X-ray Crystallography, Optical Difference Spectroscopy, NMR Relaxation, Molecular Dynamics, and Kinetics^,

Veratryl alcohol oxidation by lignin peroxidase

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Kinetics of the oxidation of p-aminobenzoic acid catalyzed by horseradish peroxidase compounds I and II.

Cited by 46 publications

References 23 publications

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Mechanism of Manganese Peroxidase Compound II Reduction. Effect of Organic Acid Chelators and pH

Binding of Salicylhydroxamic Acid and Several Aromatic Donor Molecules toArthromyces ramosusPeroxidase, Investigated by X-ray Crystallography, Optical Difference Spectroscopy, NMR Relaxation, Molecular Dynamics, and Kinetics,

Veratryl alcohol oxidation by lignin peroxidase

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Binding of Salicylhydroxamic Acid and Several Aromatic Donor Molecules toArthromyces ramosusPeroxidase, Investigated by X-ray Crystallography, Optical Difference Spectroscopy, NMR Relaxation, Molecular Dynamics, and Kinetics^,