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PubMed1970

A monophenol oxidase activity in extracts of sorghum.

A p-hydroxycinnamic acid oxidase activity was present in enzyme preparations from first internodes of Sorghum vulgare variety Wheatland milo when incubated in phosphate buffer at pH 7.5. This preparation had no classical polyphenolase activity but had both peroxidase and catalase activities. Since horseradish preparations catalyzed the same reaction, the oxidation probably is another example of a peroxidase-oxidase reaction. A second substrate was p-hydroxyphenylpyruvic acid. Ferulic acid was slightly active at low concentrations and inhibitory at higher ones. Diphenols such as caffeic and chlorogenic acids were inactive and inhibitory to p-hydroxycinnamic acid oxidation. A variety of monophenols such as tyrosine and cinnamic acid were inactive. An active substrate must have a free monophenolic group and para to this a C(3) side chain with a double bond and probably a free terminal acid group. A sulfhydryl reducing agent at the 5 millimolar level such as mercaptoethanol, reduced glutathione, or dithiothreitol was obligatory. Products were varied and were found in both the ethyl acetate-soluble and insoluble fractions after acidification of the incubation mixtures. With internode extracts, about 1 micromole of O(2) was consumed per micromole of p-hydroxycinnamic acid that disappeared in the presence of mercaptoethanol. Tetrahydrafolic acid plus mercaptoethanol were required for a second step oxidation or a parallel reaction; about 2 micromoles of O(2) were consumed per micromole of p-hydroxycinnamic acid that disappeared. Potassium cyanide, diethyldithiocarbamate, ascorbic acid, and ethylenediaminetetraacetate were inhibitory. A similar mercaptoethanol-dependent monophenol oxidase was present in preparations from green shoots that also contained a classical polyphenolase activity. The activity was present in both soluble and particulate (500 to 100,000 gravity) fractions of internodes. Preliminary studies were made of enzyme complexes in the particulate fractions capable of converting phenylalanine and tyrosine to the level of ferulic acid when the above p-hydroxycinnamic acid oxidase was blocked with ascorbic acid. The ratelimiting step was the hydroxylation of p-hydroxycinnamic acid.

Journal Article↗

PubMed1983

Ultrastructural demonstration of Fc gamma-receptors in sarcoid skin lesions.

Immune complexes of horseradish peroxidase oxidase (HRP) and rabbit IgG antibodies to HRP were used to study the Fc gamma-receptors in granulomas of cutaneous sarcoidosis. Cryostat sections of skin biopsies were incubated with HRP-anti-HRP, and the peroxidase activity was demonstrated with 3,3-diaminobenzidine tetrahydrochloride and H2O2. Most cells in the granulomas, both epithelioid and giant cells, were stained. By electron microscopy, the reaction products were localized to the plasma membranes of the cells as well-defined granular deposits. No reaction product was demonstrated intra- or extracellularly.

Granuloma↗

PubMed1975

Oxidative enzymes in the development of Fasciola hepatica L. III. The activities of oxidases and dehydrogenases in the sporocyst.

The object of the study was the investigation of the occurrence and distribution of some oxidative enzymes in the sporocyst of Fasciola hepatica L. The samples were examined for the presence of cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases, as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde-3-phosphate, glucose-6-phosphate, beta-hydroxybutyrate, L-glutamate and alcohol dehydrogenases. All of them save cytochrome oxidase were found to occur in the sporocyst. The presence and localization of these enzymes were examined by histochemical methods in various stages of development of the sporocyst. These investigations permitted it to be established that glycolytic processes are the principal way of release of energy for all developmental groups of this larva. Moreover, the functions of the tricarboxyl acid and pentose-phosphate cycles were detected and found to play a less important part in processes of energy production in the sporocyst. In addition, the functioning and metabolism of each larval organ in various stages of its development were discussed in so far as was possible on the basis of the analysis of the above-mentioned oxidative enzymes.

Alcohol Oxidoreductases↗

PubMed1984

Effects of monoclonal antibodies to bovine and Paracoccus denitrificans cytochromes c on reactions with oxidase, reductase and peroxidase.

The effects of monoclonal antibodies to bovine and Paracoccus denitrificans cytochromes c (Kuo, L.M. and Davies, H.C. (1983) Mol. Immunol. 20, 827-838) in the reactions of the cytochromes c with cytochrome c oxidase, reductase and peroxidase were studied. Spectrophotometric assays were employed, under conditions where binding of cytochrome c to the enzymes appears to be rate-limiting. Less than stoichiometric amounts of antibodies to P. denitrificans cytochrome c added to the cytochrome rendered some of it nonoxidizable or nonreducible by the P. denitrificans membrane-bound electron transport system and decreased the rate constant with the remaining cytochrome c. The antibodies appear to affect both electron transport reactions (blocking effects) with the oxidase and reductase and binding effects (effects on rate constants) and to distinguish between the two. Different ratios of antibody site to cytochrome c gave different extents of blocking of the reductase as compared with the oxidase reaction. Differences were also apparent in the effect of these antibodies on the reaction of yeast peroxidase and the oxidase with the P. denitrificans cytochrome c. Antibodies to bovine and P. denitrificans cytochromes c had considerably less effect on the reactions of the bovine cytochrome with bovine oxidase and reductase. One antibody was inhibitory to the oxidase reaction with bovine cytochrome c, but not to that with the reductase. Also, an antibody which inhibited the oxidase reaction had no effect on the reaction with yeast peroxidase. The data give evidence that the interaction areas on cytochrome c for oxidase and reductase and peroxidase are not identical, although they may be nearby.

Animals↗

PubMed1985

Single-cuvet sequential determination of triglyceride and cholesterol.

I describe a sequential method for kinetic assay of serum triglyceride and cholesterol in a single cuvet. Triglyceride is assayed first, by an ultraviolet enzymic method with ATP and NADH as the driving reagents (Clin Chem 21:1627-1629, 1975); cholesterol is then assayed with use of cholesterol oxidase, peroxidase, and the Trinder reaction. Excess NADH left by the triglyceride assay is removed by adding either pyruvate or glycerol to the cholesterol reagent; the addition prevents interference of NADH with nascent H2O2, and does not affect the apparent Km of cholesterol oxidase or the pseudo-first-order reaction of the cholesterol assay. The method, tested in both a random-access analyzer (Hitachi 705) and a batch analyzer (Olli C/D), at three concentrations, gave the following within-run CVs:3.0, 1.6, 1.5% for cholesterol; 4.0, 4.2, 5.4% for triglyceride. The corresponding between-run CVs were 12.5, 9.0, 8.1% and 12.8, 11.1, 8.9%. The calibration was linear to at least 8.0 g/L for both cholesterol and triglyceride. Interference from bilirubin, hemoglobin, and certain drugs is almost negligible. Correlation studies with reference and routine methods showed r values ranging from 0.985 to 0.995 for cholesterol, 0.984 to 0.991 for triglyceride.

Autoanalysis↗

PubMed1997

[Metronidazole effect on active oxygen production by human blood neutrophils].

The in vitro effect of metronidazole on production of active oxygen by neutrophila and in the enzymatic system of glucose-glucose oxidase-peroxidase was studied by luminol-dependent chemiluminescence. An increase in the spontaneous and zymozan-stimulated chemiluminescence and a decrease in the phorbolmyristate acetate (PMA)-stimulated chemiluminescence after 2-hour preincubation of the neutrophils with 8.5 mM of metronidazole were observed. In concentrations of 0.9 to 8.7 mM metronidazole (without washing) dose-dependently lowered the neutrophil chemiluminescence in response to the effect of PMA and ionophore A23187 and to a lesser degree to that of zymozan. In doses of 20 to 100 mM the drug had an insignificant effect on production of active oxygen by the neutrophils in response to the cell stimulation by PMA, ionophore A23187 and zymozan. The data are in conformity with the scavenger effect of metronidazole on active oxygen radicals generating in the cell-free enzymatic system both in the presence and in the absence of superoxide dismutase.

Antitrichomonal Agents↗

PubMedDate not supplied

Cytochemical evidence for aerobic pathways in Mycobacterium lepraemurium.

Three enzymes of aerobic pathways (cytochrome c oxidase, peroxidase and catalase) and one key enzyme of the tricarboxylic acid cycle (succinate dehydrogenase) were investigated for their ultrastructural localization in M. lepraemurium in infected mouse liver and in cultures of M. fortuitum as a control. All four enzymes were localized in M. fortuitum. To M. lepraemurium only cytochrome c oxidase and peroxidatic activity were detected. The localization of the latter enzyme activity was different compared with M. fortuitum. Succinate dehydrogenase was not detected in M. lepraemurium but rather surprisingly was found in the membrane of the phagosomes containing the bacteria. It is concluded that M. lepraemurium can function aerobically and has either a glyoxalate pathway or is an obligate autotroph.

Aerobiosis↗

PubMed1982

Comparative analysis of four methods for rapid glucose determination in neonates.

As an important aspect of newborn care, the rapid assessment of glucose homeostasis is often accomplished by a glucose oxidase-peroxidase chromagen test strip method, either alone or with a reflectance colorimeter. The precision of these techniques has been established, but few studies have determined accuracy in an intensive care setting. We performed the following study. During the time of routine heelstick blood sampling, the nurses collected 90 complete study sets for glucose analysis from 43 neonates. Dextrostix, Ames Meter, Chemstrip bG, and Stat Tek Meter determinations were performed according to manufacturers' instructions. Concurrent determination of blood glucose level by a glucose analyzer (Beckman) served as a standard for comparison. There was no significant difference in estimation of true blood glucose concentration among the rapid methods tested. The marked variability of results suggests only modest accuracy in estimating whole blood glucose concentration when employed in the routine neonatal clinical setting. These data indicate that the results from rapid blood glucose estimation techniques require confirmation by conventional laboratory methods prior to therapeutic intervention.

Blood Glucose↗

PubMed1975

Oxidative enzymes in the development of Fasciola hepatica L. IV. The activity of oxidases and dehydrogenases in redia.

The object of the study was to investigate the occurrence and localization of oxidative enzymes in the redia -- the third larval stage of Fasciola hepatica L. The author detected cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases (diaphorases), as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate, and alcohol dehydrogenases. The presence and localization of the enzymes in various periods of development of the redia were detected with histochemical methods. Out of the studied oxidases and dehydrogenases only cytochrome oxidase was found to be absent from the stages of young rediae. It was ascertained that the redia uses all three paths of release of energy i.e. the glycolytic, Krebs, and pentose cycles, glycolysis being presumably the principal mode of energy production.

Alcohol Oxidoreductases↗

PubMed2004

A multicommuted flow system for the determination of dextrose in parenteral and hemodialysis concentrate solutions.

A new method is presented for the automation of the determination of dextrose in parenteral and hemodialysis solutions. The method is based on multicommutation flow analysis (MCFA) and exploits enzymatic reactions providing a colored derivative that is detected spectrophotometrically (Trinder's method). The reagent, comprising glucose oxidase, peroxidase, 4-hydroxybenzoate and a buffer was obtained from a commercial kit for the determination of glycemia. The flow system used three 3-way solenoid valves operating under computer control. The necessary software was developed for the purpose and compiled in QuickBASIC 4.0 The influence of some operating variables (segment size, number of segments and reactor length) was studied. Calibration curves in the range 0-1g/L presented a slight curvature and were fitted with a second-degree polynomial (h=-0.0632C(2)+0.6039C+0.166, r(2)=0.9973, h being the peak-height (absorbance) and C the concentration in g/L). The method was validated by analyzing artificial samples presenting accurately known concentrations of dextrose, and comparing the results with the known value and with value obtained by polarimetry. Recoveries were in the range 96.6-100.2%, and the difference with the polarimetric analysis was in the range 0.1-3.3%. Precision (R.S.D.,%) was better than 2.4%. Sampling frequency of the system was 90 samples/h, with a reagent consumption of 0.14 mL per sample.

Algorithms↗

PubMed1980

Erroneously high Dextrostix values caused by isopropyl alcohol.

Glucose oxidase peroxidase chromogen reagent (Dextrostix) in combination with the Eyetone colorimeter has become increasingly popular in the rapid detection of hypoglycemic states in the newborn. Although the reliability of this system is well documented, there are several factors which can compromise the accuracy of the procedure. One such problem is the glucose reading given after a blood-alcohol combination is tested. By decreasing the light reflected from the strip, the optical electrical interpretation of the Dextrostix is altered by alcohol such that there is an apparent increase in the glucose level as read by the eyetone meter.

1-Propanol↗

PubMed2004

Spontaneous generation of reactive oxygen species in the mixture of cyanide and glycerol.

Reactive oxygen species are involved in tumor promotion or apoptosis. In assaying prooxidant or antioxidant activities, cyanide has been commonly used as an inhibitor of mitochondrial oxidases, peroxidases, or Cu,Zn-superoxide dismutase, which have an influence on intracellular levels of reactive oxygen species. It has also been used to chemically mimic hypoxia. On the other hand, glycerol has been widely used as a stabilizer of various enzymes. In particular, glycerol is required to maintain the enzymatic activities of membrane-bound NAD(P)H oxidases extracted from surrounding phospholipids. Since both cyanide and glycerol are relatively inert, they have been used concomitantly regardless of any mutual interference. In this study, we demonstrate that a mixture of glycerol and cyanide reduced cytochrome c and nitroblue tetrazolium, both of which are superoxide anion indicators. The mixture also enhanced the production of superoxide anion in the presence of redox-cycling compounds. Superoxide production by the mixture was confirmed by electron spin resonance spectra. Moreover, the mixture induced lipid peroxidation and hemolysis in human erythrocytes. These results suggest that cyanide and glycerol should be used carefully in reaction systems used to measure superoxide production or antioxidant activity. However, sucrose and sodium azide in combination do not produce such artifacts and thus may be used as an alternative.

Cyanides↗

PubMed2006

New and simple plate test for screening relative transfructosylation activity of fungi.

Several microorganisms are reported to have transfructosylation activity due to fructosyltransferase and/or fructofuranosidase activities. However, the search for other fungi with higher transfructosylation activity remains a challenge. So, a presumptive and indirect colorimetric plate assay for the evaluation of transfructosylation activity in fungi was developed which involved the simultaneous determination in the same plate of glucose and fructose released from sucrose. The method entailed the (a) glucose oxidase-peroxidase coupled reaction using phenol and 4-aminoantipyrine for determination of glucose; and (b) fructose dehydrogenase oxidation in the presence of a tetrazolium salt for determination of fructose. The presence of enzymes with transfructosylation activity was identified by the formation of pink (presence of glucose) and blue (presence of fructose) halos around the fungal colony. In conclusion, the results showed that the method is suitable for screening a large number of fungi due to its simplicity, reproducibility and rapidity and also gives a relative quantitative idea of the transfructosylation activity of different fungi species.

Ampyrone↗

PubMed1990

Two staining methods for selectively detecting isomaltase and maltase activity in electrophoresis gels.

Two methods for specifically detecting maltase, alpha-glucosidase, or isomaltase activity in electrophoresis gels are described. Both systems couple the formation of glucose by enzyme action on maltose or isomaltose to the generation of a colored product. System A uses an agarose overlay which contains substrate, glucose oxidase, peroxidase, 2,4-dichlorophenol, and 4-L-amino-phenazone. A purple color is produced at the site of enzyme activity. No hazardous chemicals are used at any stage. The stain is simple, rapid, sensitive, and inexpensive and does not interfere with subsequent protein staining. However, the stain is not permanent. System B was developed to give a permanent stain. The gel is overlaid with agarose containing substrate, glucose oxidase, phenazine methosulfate, and nitroblue tetrazolium. Glucose production results in the nitroblue tetrazolium being oxidized to an insoluble formazan with a dark blue color. This stain is also sensitive, rapid, and inexpensive but does use hazardous chemicals and if overstaining occurs this can interfere with subsequent protein staining. Neither system inactivates the localized enzymes which can be recovered from the gel if desired.

Aminopyrine↗

PubMed1979

[Effect of multivalent cations on the enzymatic determination of glucose with glucose oxidase].

Iron and copper ions, in a concentration greater than 10(-4) M, inhibit the indicator reaction of a glucose oxidase-peroxidase reagent for the enzymatic determination of glucose, when weakly complexing buffers or buffer-free reaction media are used. The addition of EDTA and other complexing agents or, time-dependently, the buffer ions themselves reverse the inhibition to a great extent. The discussed mechanism of inhibition is based on the assumption that the metal ions share in the re-oxidation of the co-enzyme of glucose oxidase.

Cations, Divalent↗

PubMed1999

Superoxide dismutase, catalase, glutathione peroxidase and xanthine oxidase in diabetic rat lenses.

The activities of the protective enzymes, superoxide dismutase, catalase, glutathione peroxidase and of xanthine oxidase, an enzyme acting as a source of O(-)(2), were measured in the lenses of alloxan-induced diabetic and control rats. Superoxide dismutase and glutathione peroxidase activities were found to be significantly decreased, while catalase and xanthine oxidase activities were increased. This means that the ratio of the oxidant/antioxidant enzymes increases in the diabetic rat lens, suggesting an increased oxidative stress. This imbalance is possibly an important contributing factor in the pathogenesis of diabetic cataract.

Animals↗

PubMed1987

Determination of pseudo-alpha- and pseudo-beta-DL-glucose by gas-liquid chromatography, high-performance liquid chromatography, and enzymatic colorimetry with glucose 2-oxidase.

Three methods have been developed for measuring pseudo-alpha- and pseudo-beta-DL-glucose (pseudo-beta-D-glucose), synthetic compounds in which the ring oxygens of alpha- and beta-DL-glucose (beta-D-glucose) have been replaced by a methylene group. Moderate sensitivity in the determination of these pseudo-glucoses dissolved in human serum was obtained by GLC (0.1 nmol) and HPLC (0.5 nmol). The colorimetric determination with glucose 2-oxidase, peroxidase, and 2,2'-azino-di-(3-ethylbenzothiazoline-6-sulfonic acid) was satisfactory for the assay of pseudo-alpha- and pseudo-beta-DL-glucose (respective sensitivities: 25 and 5 nmol). The addition of hexokinase to the colorimetric assay system made it possible to eliminate glucose present in the sample, such as serum, and the remaining pseudo-alpha- or pseudo-beta-DL-glucose in the sample solution could then be measured by a colorimetric method using glucose 2-oxidase. The methods described can be used for biochemical studies involving pseudo-alpha- and pseudo-beta-DL-glucose.

Chromatography, Gas↗

PubMed2000

Improved operational stability of peroxidases by coimmobilization with glucose oxidase.

The operational stability of peroxidases was considerably enhanced by generating hydrogen peroxide in situ from glucose and oxygen. For example, the total turnover number of microperoxidase-11 in the oxidation of thioanisole was increased sevenfold compared with that obtained with continuous addition of H(2)O(2). Coimmobilization of peroxidases with glucose oxidase into polyurethane foams afforded heterogeneous biocatalysts in which the hydrogen peroxide is formed inside the polymeric matrix from glucose and oxygen. The total turnover number of chloroperoxidase in the oxidation of thioanisole and cis-2-heptene was increased to new maxima of 250. 10(3) and 10. 10(3), respectively, upon coimmobilization with glucose oxidase. Soybean peroxidase, which normally shows only classical peroxidase activity, was transformed into an oxygen-transfer catalyst when coimmobilized with glucose oxidase. The combination catalyst mediated the enantioselective oxidation of thioanisole [50% ee (S)] with 210 catalyst turnovers.

Chloride Peroxidase↗