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PubMedDate not supplied

Plasma xanthine oxidase, superoxide dismutase and glutathione peroxidase activities and uric acid levels in severe and mild pre-eclampsia.

The aim of the present study was to measure plasma uric acid (UA) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and xanthine oxidase (XO) activities and to evaluate the relationship between these parameters and the severity of pre-eclampsia. Twenty-five pre-eclamptic, 15 healthy pregnant and 15 non-pregnant women were enrolled in this study. Increased mean plasma XO activity was found to be higher in both pre-eclampsia groups than in the healthy pregnant group. Plasma UA levels were the highest in the severe pre-eclampsia group among the study groups. SOD and GSH-Px activities were significantly lower in both pre-eclampsia groups than in the healthy pregnant group (p < 0.005 and p < 0.001, respectively). Increased XO and decreased SOD and GSH-Px activities may contribute to the pathophysiological mechanisms of pre-eclampsia and increased UA may serve a protective role responding to superoxide radicals arising from increased XO activity or other sources in pre-eclampsia.

Adult↗
PubMed1991

Ultracytochemical localization of NAD(P)H oxidase activity in the human placenta.

Ultracytochemical localization of NAD(P)H oxidase activity was demonstrated in the human term placenta by the cerium method. The activity of this enzyme was also compared to those of other oxygen-intermediates-metabolizing enzymes, such as xanthine oxidase, catalase, peroxidase and superoxide dismutase. NAD(P)H oxidase activity was exclusively confined to the apical microvillous membrane of the syncytiotrophoblast. Other enzymes studied showed no activity. We discuss the possibility that NAD(P)H oxidase might play a role in transferring substances between mother and fetus and that this enzyme might modulate placental H2O2 production.

Catalase↗
PubMedDate not supplied

Effect of 2-benzoxazolinone (BOA) on seedling growth and associated biochemical changes in mung bean (Phaseolus aureus).

BOA (2-benzoxazolinone) is a potent phytotoxin present in several graminaceous crops such as rye, maize and wheat. Due to its wide range of phytotoxicity, it is considered as a potential pesticide. A study was conducted to explore the impact of BOA on the radicle and plumule elongation of mung bean (Phaseolus aureus) and associated changes in the macromolecular content - proteins and carbohydrates - and activities of enzymes like amylases, proteases, polyphenol oxidases and peroxidases. BOA significantly reduced the radicle and plumule length of P. aureus, and the contents of proteins and carbohydrates in both root and leaf tissue. On the other hand, activities of hydrolytic enzymes - proteases, amylases, polyphenol oxidases and peroxidases - increased substantially in both root and leaf tissue of P. aureus upon BOA exposure. This indicated that BOA treatment induced stress in P. aureus and enhanced enzyme activities to counter the induced stress and continue the growth. In other words, BOA-induced stress altered the plant biochemical status and related enzyme activities resulting in increased metabolism that serves to provide protection against cellular injury. Such studies providing information about the biomolecular content and enzymatic activities in response to natural products serve as clues for furtherance of knowledge about the modes of action of natural compounds of commercial interest.

Benzoxazoles↗
PubMedDate not supplied

The substitution of glucose-antiglucose oxidase complex (GAG) for peroxidase-antiperoxidase (PAP) in immunohistochemical studies of skin.

The substitution of glucose-antiglucose oxidase complex (GAG) for peroxidase antiperoxidase (PAP) in the Sternberger three-layer unlabeled antibody method avoids the problems associated with the use of the chromogen 3,3,diaminobenzidine (DAB). The blue final reaction product obtained using the GAG complex is not obscured by melanin granules, which is often the case when using the PAP-DAB combination. The replacement of PAP with GAG complexes facilitates the detection of melanocytes in melanoma and blue nevi. The absence of endogenous glucose oxidase in mammals provides for greater image contrast, which is not possible using alternative chromogens and immunoperoxidase.

Glucose Oxidase↗
PubMed1986

Tyrosinase catalyzes an unusual oxidative decarboxylation of 3,4-dihydroxymandelate.

Tyrosinase usually catalyzes the conversion of monophenols to o-diphenols and oxidation of diphenols to the corresponding quinones. However, when 3,4-dihydroxymandelic acid was provided as the substrate, it catalyzed an unusual oxidative decarboxylation reaction generating 3,4-dihydroxybenzaldehyde as the sole product. The identity of the product was confirmed by high-performance liquid chromatography (HPLC) as well as ultraviolet and infrared spectral studies. None of the following enzymes tested catalyzed the new reaction: galactose oxidase, ceruloplasmin, superoxide dismutase, ascorbate oxidase, dopamine beta-hydroxylase, and peroxidase. Phenol oxidase inhibitors such as phenylthiourea, potassium cyanide, and sodium azide inhibited the reaction drastically, suggesting the participation of the active site copper of the enzyme in the catalysis. Mimosine, a well-known competitive inhibitor of tyrosinase, competitively inhibited the new reaction also. 4-Hydroxymandelic acid and 3-methoxy-4-hydroxymandelic acid neither served as substrates nor inhibited the reaction. Putative intermediates such as 3,4-dihydroxybenzyl alcohol and (3,4-dihydroxybenzoyl)formic acid did not accumulate during the reaction. Oxidation to a quinone methide derivative rather than conventional quinone accounts for this unusual oxidative decarboxylation reaction. Earlier from this laboratory, we reported the conversion of 4-alkylcatechols to quinone methides catalyzed by a cuticular phenol oxidase [Sugumaran, M., & Lipke, H. (1983) FEBS Lett. 155, 65-68]. Present studies demonstrate that mushroom tyrosinase will also catalyze quinone methide production with the same active site copper if a suitable substrate such as 3,4-dihydroxymandelic acid is provided.

Basidiomycota↗
PubMed1972

Involvement of Peroxidase and Indole-3-acetic Acid Oxidase Isozymes from Pear, Tomato, and Blueberry Fruit in Ripening.

Protein extracts were obtained from climacteric fruits (pear, tomato) and nonclimacteric fruits (blueberry) during various stages of ripening. The use of a gel electrophoresis technique revealed a consistent reinforcement in indoleacetic acid oxidase but not in peroxidase isozymes during ripening. The significance of the results is discussed in relation to the resistance of fruits to ripening and ethylene action.

Journal Article↗
PubMed2005

Light promotes the synthesis of lignin through the production of H2O2 mediated by diamine oxidases in soybean hypocotyls.

In order to analyze the relationship between polyamine oxidative degradation induced by light and the Lignin synthesis in cell walls, the activities of diamine oxidases and peroxidase, the contents of H2O2 and lignin, and the growth of hypocotyls in soybean [Glycine max (Linn.) Merr.] grown under tight or in darkness were investigated. In comparison with the dark treatment, light irradiation significantly inhibited the growth of soybean hypocotyls and promoted the activities of diamine oxidases and peroxidase as well as the accumulation of H2O2 and lignin. Treatments with the different concentrations of diamine oxidase inhibitors (2-hydroxyethylhydrazine and aminoguanidine) under the light condition inhibited diamine oxidase activity, and decreased the contents of H2O2 and lignin. The results provide evidence for the hypothesis that light irradiation could promote the accumulation of H2O2 and lignin in cell walls by activating polyamine oxidative degradation mediated by diamine oxidases.

Amine Oxidase (Copper-Containing)↗
PubMed1978

Comparative histochemical study of the enzyme changes in the ovary and uterus of mammals with special references to steroidogenesis.

A comparative study of the enzymes delta5-3beta-HSD, cytochrome oxidase and peroxidase has been made in the ovaries and uterus of mammals (mouse, guinea pig, cat and dog) during various reproductive phases. The granulosa cells of developing follicles, hypertrophied interstitial cells of thecal origin and the luteal cells show intense delta5-3beta-HSD and cytochrome oxidase activity. Peroxidases are found to be present in the corpus luteum and the epithelial cords of thecal origin. delta5-3beta-HSD and cytochrome oxidase activity is localized to the endometrium and myometrium of mature and pregnant uterus of mouse and guinea pig, while peroxidase is seen only in the decidua and endometrial glands of pregnant animals. The significance of these enzymes is discussed in relation to the cellular basis of luteinization and steroid hormone synthesis.

Animals↗
PubMed2000

Southern blot screening for lignin peroxidase and aryl-alcohol oxidase genes in 30 fungal species.

Screening to detect genes encoding lignin peroxidase (LiP) and aryl-alcohol oxidase (AAO) has been carried out with 30 fungal strain using DNA probes from genes lpo of Phanerochaete chrysosporium (encoding LiP isoenzyme H8) and aao of Pleurotus eryngii. Evidence for the presence of genes closely related to lpo was found in Bjerkandera adusta, Fomes fomentarius, Ganoderma applanatum, Ganoderma australe, Lentinula degener, Peniophora gigantea, P. chrysosporium, Phanerochaete flavido-alba and Trametes tersicolor, whereas the gene aao was detected in Pleurotus species and B. adusta. The presence of both genes was only detected in B. adusta. These results suggest that different enzymatic system, formed by enzymes encoded by different genes, are responsible for lignin degradation by white-rot fungi.

Alcohol Oxidoreductases↗
PubMed2001

Cell-wall proteins from Sitka spruce xylem are selectively insolubilised during formation of dehydrogenation polymers of coniferyl alcohol.

Extracts from the lignifying xylem of Sitka spruce that were enriched in cell-wall-associated glycoproteins contained peroxidase and oxidase activity and readily formed lignin-like water-insoluble dehydrogenation polymers (DHPs) from coniferyl alcohol (CA) when supplied with H2O2. During the formation of DHPs, the abundance of a number of polypeptides in the extracts was diminished. However, these polypeptides were also diminished in control reactions that contained H2O2 but lacked CA. Polypeptides could be recovered from the DHPs by heating in SDS-PAGE sample buffer but no insolubilised polypeptides could be recovered from the + H2O2 reactions. Although most of the DHP-bound polypeptides were easily removed by pre-washing the DHPs, two polypeptides at 125 and 52 kDa remained tightly bound to the DHPs. The abundance of the two DHP-bound polypeptides mirrored the diminution of 120 and 46 kDa polypeptides in the extracts. The N-terminal protein sequences of the 125 and 52 kDa DHP-bound polypeptides were essentially identical to the sequences obtained from the 120 and 46 kDa polypeptides from the extracts, which confirmed that the DHP-bound polypeptides were derived from these soluble polypeptides. The 125-kDa DHP-bound polypeptide yielded an N-terminal protein sequence that was identical to a laccase-type oxidase previously identified in similar extracts from lignifying Sitka xylem. The N-terminal protein sequence of the 46-kDa polypeptide was homologous with a subset of plant peroxidases. The DHPs had tightly bound peroxidase and oxidase activity, which suggested that these polypeptides were active in their insolubilised state. The mechanism and selectivity of insolubilisation of these enzymes is discussed.

Amino Acid Sequence↗
PubMed1982

Distribution of oxidases in the testis of buffalo, goat and ram: an histochemical study.

Peroxidase, monoamine oxidase (MAO) and cytochrome oxidase (CCO) have been histochemically localized in the testis of buffalo, goat and ram. The results in these three species were more or less similar. Peroxidase was localized only in the interstitial tissue and could be used as a marker enzyme for this testicular compartment. MAO and CCO were present in both the interstitial tissue and the seminiferous tubules. The detailed patterns of MAO and CCO distribution were also similar and showed cyclic changes in the spermatids which have not been reported before. The results have been compared and contrasted with those of previous workers and their possible physiological significance discussed.

Animals↗
PubMed1977

Characteristics of tyrosinase in B16 melanoma.

Tyrosine hydroxylase, dopa oxidase, and peroxidase activities were studied in soluble fractions of B16 melanoma tumor homogenates by polyacrylamide gel disc electrophoresis. Stained gels were scanned photometrically and gel slices were assayed radiometrically. In these preparations, the two bands of tyrosine hydroxylating activity were completely separated from the peroxidase activity but coincided with two major bands of dopa oxidase activity. The third dopa oxidase band coincided with the single band of peroxidase activity. The soluble fraction of cultured cell homogenates had no peroxidase activity, but the two tyrosine hydroxylase bands coincided exactly with the two dopa oxidase bands. Therefore, in the soluble fraction of the murine melanoma bifunctional tyrosinase does exist as two electrophoretically separable forms which are independent of peroxidase.

Animals↗
PubMed1991

Identification of a specific manganese peroxidase among ligninolytic enzymes secreted by Phanerochaete chrysosporium during wood decay.

The specific enzymes associated with lignin degradation in solid lignocellulosic substrates have not been identified. Therefore, we examined extracts of cultures of Phanerochaete chrysosporium that were degrading a mechanical pulp of aspen wood. Western blot (immunoblot) analyses of the partially purified protein revealed lignin peroxidase, manganese-dependent peroxidase (MnP), and glyoxal oxidase. The dominant peroxidase, an isoenzyme of MnP (pI 4.9), was isolated, and its N-terminal amino acid sequence and amino acid composition were determined. The results reveal both similarities to and differences from the deduced amino acid sequences from cDNA clones of dominant MnP isoenzymes from liquid cultures. Our results suggest, therefore, that the ligninolytic-enzyme-encoding genes that are expressed during solid substrate degradation differ from those expressed in liquid culture or are allelic variants of their liquid culture counterparts. In addition to lignin peroxidase, MnP, and glyoxal oxidase, xylanase and protease activities were present in the extracts of the degrading pulp.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Stabilization of activity of oxidoreductases by their immobilization onto special functionalized glass and novel aminocellulose film using different coupling reagents.

Glucose oxidase (GOD), horseradish peroxidase (HRP), and lactate oxidase (LOD) were covalently immobilized on special NH(2)-functionalized glass and on a novel NH(2)-cellulose film via 13 different coupling reagents. The properties of these immobilized enzymes, such as activity, storage stability, and thermostability, are strongly dependent on the coupling reagent. For example, GOD immobilized by cyanuric chloride on the NH(2)-cellulose film loses approximately half of its immobilized activity after 30 days of storage at 4 degrees C or after treatment at 65 degrees C for 30 min. In contrast, GOD immobilized by L-ascorbic acid onto the same NH(2)-cellulose film retains 90% of its initial activity after 1 year of storage at 4 degrees C and 92% after heat treatment at 65 degrees C for 30 min. Unlike GOD, in the case of LOD only immobilization on special NH(2)-functionalized glass, e.g., via cyanuric chloride, led to a stabilization of the enzyme activity in comparison to the native enzyme. The operational stability of immobilized HRP was up to 40 times higher than that of the native enzyme if coupling to the new NH(2)-cellulose film led to an amide or sulfonamide bond. Regarding the kinetics of the immobilized enzymes, the coupling reagent plays a minor role for the enzyme substrate affinity, which is characterized by the apparent Michaelis constant (K(M,app)). The NH(2)-functionalized support material as well as the immobilized density of the protein and/or immobilized activity has a strong influence on the K(M,app) value. In all cases, K(M,app) decreases with increasing immobilized enzyme protein density and particularly drastically for GOD.

Bacterial Proteins↗
PubMed1988

Oxygen-independent induction of enzyme activities related to oxygen metabolism in yeast by copper.

Aerobic growth of Saccharomyces cerevisiae in the presence of CuSO4 (between 0.1 and 1 mM) caused a generalized induction of major enzyme activities involved in 'housekeeping' routes of oxygen metabolism (cytochrome oxidase, glutathione peroxidases and catalase) which were comparable to or higher than that observed with Cu,Zn-superoxide dismutase. Fumarase and glutathione transferase, tested as controls for oxygen-unrelated activities, were found to decrease under the same conditions. In the absence of oxygen, copper addition to yeast resulted in significant increases of Cu,Zn-superoxide dismutase and glutathione peroxidases and a slight increase of cytochrome oxidase, with catalase remaining undetectable irrespective of whether or not copper was present. Other metal ions tested (Mn2+, Co2+) were unable to produce such effects. It is concluded that copper has a general inducing effect on enzymes related to metabolism of oxygen and oxygen derivatives, which is mediated neither by formation of O2-. and H2O2 nor by interaction with copper-specific apoproteins. These results point to a general role of copper as regulator of the expression of major enzyme activities involved in biological oxygen activation.

Aerobiosis↗
PubMed1977

Noradrenaline innervation of the spinal cord studied by the horseradish peroxidase method combined with monoamine oxidase staining.

The origin of the spinal cord noradrenaline (NA) has been investigated by means of the horseradish peroxidase (HRP) method, combined with monoamine oxidase staining (Glenner) to identify the NA neurons. Following the injection of HRP to the various levels of rat spinal cord, cervical to sacral cord, A1-3, 5-7 NA neuron groups were labeled with HRP. They showed almost the same distribution pattern regardless of difference in the injected segment. Labeled NA neurons in A6 were concentrated in the ventral division of the locus coeruleus, which continued to the labeled NA neurons in the subcoeruleus area. The HRP positive neurons in the pons outnumbered those of the medulla oblongata. As the NA neurons described above were considered to be the source of NA in the forebrain, such as the hypothalamus and preoptic area, the possibility that the same NA neurons might innervate both the forebrain and spinal cord has been presented.

Adrenergic Fibers↗
PubMed1995

Study of antioxidant properties of metal aspartates.

The effects of Zn, Mg, Cr, Cu, and Mn aspartates, their commercial formulation Inzolen, and the individual commercial medicine Unizinc, on oxygen radical production by enzymes [xanthine oxidase, horseradish peroxidase, and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase] and phagocytic cells (human blood leukocytes) have been studied. The formation of oxygen radicals was measured by luminol- and lucigenin-amplified chemiluminescence and by the reduction of cytochrome c. All these compounds (excluding Cr aspartate) turn out to be inhibitors of oxygen radical formation in the systems studied (excluding horseradish peroxidase). Their inhibitory activities were a consequence of both the scavenging of free radicals and the inhibition of xanthine oxidase and NADPH oxidase activities. As expected, the most active free-radical scavengers were transition metal Cu and Mn aspartates, which mimicked the activities of copper-zinc and manganese dismutases. However, surprisingly non-transition metal Zn and Mg aspartates were also able to scavenge oxygen radicals. It was suggested that the scavenging activities of Zn and Mg aspartates may be explained by affecting the rate of spontaneous dismutation of the superoxide ion. In addition, it was found that Zn aspartate is an efficient inhibitor of the formation of the most reactive hydroxyl radicals. These antioxidant properties of Zn aspartate make it important in medicine for the prevention and treatment of free radical pathologies.

Antioxidants↗