Peroxidase-catalyzed NADH oxidation

In analyzing oscillations in peroxidase catalyzed aerobic oxidation of NADH, Fedkina et al. (1981) experimentally obtained oscillatory results in concentrations of peroxidase compound Co(III) and 02 and NADH. They studied the influence of temperature change on the oscillations. 

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],... 

Indicine IV-oxide (169) (Scheme 36) is a clinically important pyrrolizidine alkaloid being used in the treatment of neoplasms. The compound is an attractive drug candidate because it does not have the acute toxicity observed in other pyrrolizidine alkaloids. Indicine IV-oxide apparently demonstrates increased biological activity and toxicity after reduction to the tertiary amine. Duffel and Gillespie (90) demonstrated that horseradish peroxidase catalyzes the reduction of indicine IV-oxide to indicine in an anaerobic reaction requiring a reduced pyridine nucleotide (either NADH or NADPH) and a flavin coenzyme (FMN or FAD). Rat liver microsomes and the 100,000 x g supernatant fraction also catalyze the reduction of the IV-oxide, and cofactor requirements and inhibition characteristics with these enzyme systems are similar to those exhibited by horseradish peroxidase. Sodium azide inhibited the TV-oxide reduction reaction, while aminotriazole did not. With rat liver microsomes, IV-octylamine decreased... 

Horseradish Peroxidase Catalyzed Oxidation of Reduced Pyridine Nucleotides (NADH)... 

Yamazaki and collaborators studied the horseradish peroxidase catalyzed oxidation of NADH by oxygen, 02, in an open system, and observed oscillations in concentrations of oxygen (1965) and of NADH (1967). Degn (1968, 1969) also observed oscillations in a similar peroxidase catalyzed reaction. Degn and Mayer (1969) investigated the theoretical considerations of these reactions and more recently Olsen and Degn (1977) observed chaotic oscillations in the peroxidase catalyzed oxidation of NADH by 02 in an open system, Fig. III.31. 

Fig. III.3I. Chaotic oscillations in horesradish peroxidase catalyzed oxidation of NADH by 02. Cases a), b) and c) are for decreasing concentrations of peroxidase. (From Olsen and Degn (1977))...

Oxidoreductases these enzymes catalyze redox reactions. Examples are oxidases that catalyze oxidation of a substrate by reducing molecular oxygen (02), and peroxidases that reduce H202. Laccases (EC 1.10.3.2) are oxidases that catalyze the oxidation of (poly)phenolic substrates. Reductases and dehydrogenases (EC 1.1.1) catalyze the reduction of carbonyls, using NADH/NADPH cofactors. Catalases (EC 1.11.1.6) catalyze the decomposition of H202 to 02 and H20. 

Reigosa, M.J. et al. (2001) Comparison of physi-otogical effects of allebchemicals and commercial herbicides. Allelopathy J. 8,211-220 Rojas, M.C. et al. (1997) Stimulatory effect of DIMBOA on NADH oxidation catalyzed by borseradisb peroxidase. Phytochemistry 46, 11-15... 

Many dehydrogenase enzymes catalyze oxidation/reduction reactions with the aid of nicotinamide cofactors. The electrochemical oxidation of nicotinamide adeniiw dinucleotide, NADH, has been studied in depthThe direct oxidation of NADH has been used to determine concentration of ethanol i s-isv, i62) lactate 157,160,162,163) pyTuvate 1 ), glucose-6-phosphate lactate dehydrogenase 159,161) alanine The direct oxidation often entails such complications as electrode surface pretreatment, interferences due to electrode operation at very positive potentials, and electrode fouling due to adsorption. Subsequent reaction of the NADH with peroxidase allows quantitation via the well established Clark electrode. 

A number of autoxidation reactions exhibit exotic kinetic phenomena under specific experimental conditions. One of the most widely studied systems is the peroxidase-oxidase (PO) oscillator which is the only enzyme reaction showing oscillation in vitro in homogeneous stirred solution. The net reaction is the oxidation of nicotinamide adenine dinucleotide (NADH), a biologically vital coenzyme, by dioxygen in a horseradish peroxidase enzyme (HRP) catalyzed process ... 

The degradation of cholesterol leads to the production of bile acids which are structurally closely related to various steroid hormones. (3-Hydroxysteroid dehydrogenase (EC 1.1.1.51) catalyzes the NAD+-de-pendent oxidation of 3(3-, 17(3- and some l6(3-hydroxysteroids to the respective ketosteroids. The enzyme has been adsorbed on a carbon electrode modified by NMP+TCNQ and the NADH liberated in the reaction oxidized anodically (Albery et al., 1987a). Campanella et al. (1984) employed an enzyme sequence electrode composed of NAD+-de-pendent steroid dehydrogenase and horseradish peroxidase for assay of 7a-hydroxysteroids. 

Polymerization, the final step of lignin biosynthesis, is catalyzed by peroxidases which are frequently found in cell walls. Obviously the peroxidases produce HgOg from NAD(P)H involving the superoxide free radical ion as an intermediate of the complex reaction chain. An NAD-specific malate dehydrogenase produces NADH used as electron donor in the formation of HgOg by oxidation of malate. 

In this section, we turn to experiments on the horse radish peroxidase (HRP) reaction [14,15], which is the oxidation of nicotinamide adenine dinucleotide (NADH) catalyzed by HRP... 

Oscillating chemiluminescence has been observed in the H2O2/KSCN/ CuS04/NaOH/luminol system there are two types of oscillation, and the low-intensity mode may involve the reaction of superoxide with luminol. A simplified mechanism for the methylene-blue/HS /02 oscillation in a CSTR has been proposed. Experimental and modeling structures of oscillation in the C102/l2/malonic acid system show that the oscillations are not due to autocatalysis but to self-inhibition in the ClOf/I reaction. A study of the oxidation of hexacyanoferrate(II) by bromine is concluded to involve the formation of Brf as an intermediate, formed in the first step. The aerobic oxidation of NADH catalyzed by horse radish peroxidase... 

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