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PubMed2001

[Peroxidase activity in human uterine tissue: connection with clinico-morphological features of endometrial cancer].

Peroxidase activity was determined in 98 patients with endometrial cancers. In 34 patients with endometrial cancers, the activity of the enzyme was also detected in the neighbouring unchanged (normal) tissues. It was shown that in tumor tissues the level of peroxidase activity was higher than in normal ones. The peroxidase activity increased both in tumor and normal endometrium when clinical and morphological characteristics of tumor were unfavourable, i.e. at later stages of the disease, deeper invasion to myometrium, lower levels of differentiation of tumors. The peroxidase activity was somewhat higher in post-menopausal women; however, no direct was found between the activity of this enzyme in malignant and normal tissues, on the one hand, and the menstrual status of patients with different clinical and morphological characteristics of endometrial cancer, on the other relationship. The level of peroxidase activity in normal and malignant tissues was more pronounced in advanced and poorly-differentiated tumors. It seems important to use peroxidase activity as a prognostic factor and as a possible marker of endometrial cancer hormone-dependence that needs further investigation.

Endometrial Neoplasms↗
PubMed2001

Cathepsin B and complement C3 are major comigrants in the estrogen-induced peroxidase fraction of rat uterine fluid.

The luminal fluid of estrogen or DES-stimulated uterus of immature rats contains 10-12 isoforms of peroxidase between pI 4.5-6.0. N-terminal amino acid sequencing of diaminobenzidine-peroxidase bands eluted from IEF and SDS-PAGE gels showed the presence of cathepsin B and the complement family of proteins as the major comigrants. Sequential treatment of uterine fluid by cation, anion, and size exclusion chromatography resulted in a five-fold purification of peroxidase having a specific activity of 273 units/mg. Mass spectrometric studies of bands isolated from SDS-PAGE gels from the size-exclusion purified peroxidase fraction showed the presence of complement C3 along with novel previously uncharacterized proteins. Two dimensional electrophoresis followed by N-terminal amino acid sequencing confirmed the presence of cathepsin B isoforms and isoforms of a novel protein at approximately 87 kDa. Identification by mass spectrometry from the database for this novel protein was inconclusive but could most likely be a candidate for estrogen-induced peroxidase. Results conclusively prove that cathepsin B and complement C3 are major proteins in the estrogen-induced peroxidase fraction of uterine fluid.

Amino Acid Sequence↗
PubMedDate not supplied

[Histochemical assessment of immunoreactivity of thyroid peroxidase and its correlation with biochemical activity].

BACKGROUND: Peroxidase content has been recently evaluated in normal thyroid and in different thyroid disorders by biochemical, histochemical, ultrastructural and immunocytochemical methods Nevertheless immunocytochemical detection of thyroid peroxidase in thyroid samples conventionally processed for histology hes never been done using a commercially available antibody, neither its correlation with the biochemical activity on adjacent samples. METHODS: In this study we have analyzed normal thyroid tissue (3 patients), follicular adenoma (2 patients) and multinodular goiter (2 patients) conventionally processed for histology and stiined by immunocytochemistry (Avidin Biotin System) using a polyclonal (rabbit) antibody for horseradish peroxidase (Serotec). Biochemical assay was performed on adjacent samples according to Hosoya method. RESULTS: Normal thyroid showed peroxidase immunoresectivity in the majority of follicular celis; neoplastic cells of adenomas were variably stained. Biochemical assay showed positive correlation with ICC ranging from 20.4 mg/mg/prot a in multinodular goiter to 42.12 in normal thyroid, up to 122 of follicular adenoma. CONCLUSIONS: Peroxidase content in the thyroid gland may be of clinical interest in several thyroid diseases, and in this study we have demonstrated that thyroid peroxidase can be detected by ICC in routinely processed thyroid samples using a commercially available antibody.

Humans↗
PubMed1992

Hammett rho sigma correlation for the inhibition by indoles of coniferyl alcohol oxidation catalyzed by cell wall peroxidases.

The inhibitory effect of indole-3-acetic acid, and of its peroxidase-mediated degradation products of an indole nature, on the oxidation rate of coniferyl alcohol catalyzed by cell wall peroxidases has been studied. The results show that the inhibitory effect of indole-3-acetic acid and indole-3-carbinol may be explained, in part, by their properties as peroxidase substrates. However, I50 values for a series of indole compounds not regarded as peroxidase substrates show a good correlation with the electron-donating or electron-withdrawing nature of the 3-substituents, as judged by the linearity of the Hammett rho sigma plot. These results suggest that although the properties of indole compounds as peroxidase substrates may be responsible, in part, for their inhibitory effects on the peroxidase-mediated oxidation of coniferyl alcohol, the inhibitory effect appears to be mainly determined by the acidity of the imino group of the indole nucleus.

Catalysis↗
PubMed2003

[Determination of peroxidase positive cells in semen: is it a secure parameter for the diagnosis of silent genital infections?].

BACKGROUND: The presence of leukocytes, detected by peroxidase test in semen, can be a good indicator of infections in the male genital tract. Peroxidase positive cells have been positively correlated with elevated values of elastase, one of the major proteases liberated by granulocytes at the inflammation place. However, seminal granulocytes may not be adequately detected by the peroxidase test in comparison with immunological methods. AIM: To correlate the determination of peroxidase positive cells with the elastase level in the seminal plasma. MATERIAL AND METHODS: Seminal plasma from 64 patients with a high number of round cells (> 106/ml) in semen, was studied. Correlation analysis was done using the Pearson correlation coefficient. RESULTS: No correlation between the level of granulocyte elastase and the number of peroxidase positive cells (r = 0.2237, p > 0.05), or even the number of round cells (r = 0.03934, p > 0.05) was observed. CONCLUSIONS: Our results suggest that the determination of peroxidase positive cells is not a reliable indicator of leukocytes in the seminal plasma and their absence do not discard a silent genital tract infection.

Biomarkers↗
PubMedDate not supplied

Metabolism of 3-tert-butyl-4-hydroxyanisole by horseradish peroxidase and hydrogen peroxide.

3-Tert-butyl-4-hydroxyanisole (3-BHA) was metabolized in the presence of horseradish peroxidase and hydrogen peroxide to 2-tert-butyl-p-benzoquinone (TBQ), 2,3-epoxy-5-tert-butyl-1,4-benzoquinone (TBQ-epoxide), and two known dimers. The formation of TBQ from 3-BHA required both horseradish peroxidase and hydrogen peroxide. When 2.5 mM 3-BHA was incubated with horseradish peroxidase and hydrogen peroxide, the formation of TBQ increased with hydrogen peroxide concentration up to 5 mM and decreased gradually at higher concentrations of hydrogen peroxide. On the other hand, the formation of TBQ-epoxide from 3-BHA increased, depending on hydrogen peroxide concentration at higher concentrations than 1 mM. In incubating 2-tert-butylhydroquinone (TBHQ) with horseradish peroxidase and hydrogen peroxide, TBHQ was rapidly oxidized to TBQ, and then TBQ-epoxide was also produced at concentrations more than 2.5 mM of hydrogen peroxide. In the absence of horseradish peroxidase, the incubation of TBQ with hydrogen peroxide resulted in TBQ-epoxide production. These results suggest that 3-BHA is metabolized to TBHQ, which is rapidly oxidized to TBQ, by horseradish peroxidase and hydrogen peroxide, and then TBQ is converted to TBQ-epoxide by only hydrogen peroxide.

Butylated Hydroxyanisole↗
PubMed1992

Mature eosinophils stimulated to develop in human-cord blood mononuclear cell cultures supplemented with recombinant human interleukin-5. II. Vesicular transport of specific granule matrix peroxidase, a mechanism for effecting piecemeal degranulation.

The mechanism of piecemeal degranulation by human eosinophils was investigated. Mature eosinophils that developed in rhIL-5-containing conditioned media from cultured human cord blood mononuclear cells were prepared for ultrastructural studies using a combined technique to image eosinophil peroxidase by cytochemistry in the same sections on which postembedding immunogold was used to demonstrate Charcot-Leyden crystal protein. Vesicular transport of eosinophil peroxidase from the specific granule matrix compartment to the cell surface was associated with piecemeal degranulation. This process involved budding of eosinophil peroxidase-loaded vesicles and tubules from specific granules. Some eosinophil peroxidase that was released from eosinophils remained bound to the cell surface; some was free among the cultured cells. Macrophages and basophils bound the released eosinophil peroxidase to their plasma membranes, internalized it in endocytotic vesicles, and stored it in their respective phagolysosomes and secretory granules. Charcot-Leyden crystal protein was diffusely present in the nucleus and cytoplasm of IL-5-stimulated mature eosinophils. Extensive amounts were generally present in granule-poor and subplasma membrane areas of the cytoplasm in contrast to eosinophil peroxidase, which was secreted and bound to the external surface of eosinophil plasma membranes. These studies establish vesicular transport as a mechanism for emptying the specific eosinophil granule matrix compartment during IL-5-associated piecemeal degranulation.

Blood Cells↗
PubMed1992

Active-site structural comparison of streptococcal NADH peroxidase and NADH oxidase. Reconstitution with artificial flavins.

The apoproteins of the streptococcal NADH peroxidase (H2O2----2H2O) and NADH oxidase (O2----2H2O) stabilize the neutral forms of 6-hydroxy- and 6-mercapto-FAD, respectively. The redox behavior of the 6-hydroxy-FAD peroxidase closely mimics that of the native enzyme with both dithionite and NADH. Both oxidase and peroxidase preferentially stabilize the N(1)-protonated p-quinonoid species of 8-mercapto-FAD, and the 8-position of the bound flavin is accessible to solvent in both proteins. The 8-mercapto-FAD peroxidase yields an EH2 spectrum on reduction virtually identical to that seen with 8-mercapto-FAD glutathione reductase, but no distinct EH2.NADH form appears. The dramatic decreases in reactivity at the flavin 2- and 4-positions for both the peroxidase and the oxidase, assessed with the reconstituted 2- and 4-thio-FAD enzymes, suggest that these positions are buried by elements of both protein structures. Furthermore, reconstitution of the peroxidase with the higher potential 2- and 4-thioflavins yields enzyme forms which are fully reducible with 1.4 eq of NADH/FAD, giving rise to stable thio-FADH2.NAD+ complexes. This behavior closely mimics that of the native NADH oxidase and provides further evidence supporting the hypothesis that a major functional distinction between the two structurally related proteins is determined by the redox potential and/or NADH reactivity of the bound flavin coenzyme.

Binding Sites↗
PubMed1990

Heterogeneity among the flavin-containing NADH peroxidases of group D streptococci. Analysis of the enzyme from Streptococcus faecalis ATCC 9790.

Polyclonal antisera prepared against the purified NADH peroxidase from Streptococcus faecalis ATCC 9790 (Enterococcus hirae) do not cross-react with the ATCC 11700 enzyme. Comparative tryptic maps of the two proteins indicate that the differences in primary structures extend beyond those localized to respective antigenic epitopes. Alignments of the NH2-terminal and active-site cysteinyl peptide sequences of the two streptococcal peroxidases reveal identities of 50 and 67% in the respective overlap regions. Dithionite titrations of the ATCC 9790 enzyme reveal a separation in potentials (E2 - E1) for the nonflavin and flavin redox centers of 39 mV, a value nearly 50 mV lower than that observed with the ATCC 11700 peroxidase. Despite these changes in redox behavior NADH titrations of the ATCC 9790 enzyme give rise to both EH2 and EH2.NADH species as previously observed. The enzyme turnover number with hydrogen peroxide is approximately 60% that of the ATCC 11700 peroxidase; the ATCC 9790 peroxidase is also inhibited during turnover with ethyl hydroperoxide. These findings suggest that the flavoprotein NADH peroxidases may exhibit greater diversity among the group D streptococci than previously observed with the widely distributed enzymes of the related flavoprotein disulfide reductase class.

Amino Acid Sequence↗
PubMed1987

Homology among multiple extracellular peroxidases from Phanerochaete chrysosporium.

The extracellular peroxidases of Phanerochaete chrysosporium were separated into 21 proteins by analytical isoelectric focusing. Fifteen of these enzymes oxidized veratryl alcohol (lignin peroxidases) in the presence of H2O2. Six enzymes were Mn(II)-dependent peroxidases. The Mn(II)-dependent enzymes appeared and reached their maximal activity earlier than the lignin peroxidases in the cultures. Peptide mapping, amino acid analysis, and reaction against specific antibodies showed that all the Mn(II)-dependent peroxidases were probably products of one gene. A great degree of homology was also present among the various lignin peroxidases.

Amino Acids↗
PubMed1988

Spectral characterization of manganese peroxidase, an extracellular heme enzyme from the lignin-degrading basidiomycete, Phanerochaete chrysosporium.

Manganese peroxidase (MnP) is a component of the lignin degradation system of the basidiomycetous fungus, Phanerochaete chrysosporium. This novel MnII-dependent extracellular enzyme (Mr = 46,000) contains a single protoporphyrin IX prosthetic group and oxidizes phenolic lignin model compounds as well as a variety of other substrates. To elucidate the heme environment of this enzyme, we have studied its electron paramagnetic resonance and resonance Raman spectroscopic properties. These studies indicate that the native enzyme is predominantly in the high-spin ferric form and has a histidine as fifth ligand. The reduced enzyme has a high-spin, pentacoordinate ferrous heme. Fluoride and cyanide readily bind to the sixth coordination position of the heme iron in the native form, thereby changing MnP into a typical high-spin, hexacoordinate fluoro adduct or a low-spin, hexacoordinate cyano adduct, respectively. EPR spectra of 14NO- and 15NO-adducts of ferrous MnP were compared with those of horseradish peroxidase (HRP); the presence of a proximal histidine ligand was confirmed from the pattern of superhyperfine splittings of the NO signals centered at g approximately equal to 2.005. The appearance of the FeII-His stretch at approximately 240 cm-1 and its apparent lack of deuterium sensitivity suggest that the N delta proton of the proximal histidine of the enzyme is more strongly hydrogen bonded than that of oxygen carrier globins and that this imidazole ligand may be described as having a comparatively strong anionic character. Although resonance Raman frequencies for the spin- and coordination-state marker bands of native MnP, nu 3 (1487), nu 19 (1565), and nu 10 (1622 cm-1), do not fall into frequency regions expected for typical penta- or hexacoordinate high-spin ferric heme complexes, ligation of fluoride produces frequency shifts of these bands very similar to those observed for cytochrome c peroxidase and HRP. Hence, these data strongly suggest that the iron in native MnP is predominantly high-spin pentacoordinate. Analysis of the Raman frequencies indicates that the dx2-y2 orbital of the native enzyme is at higher energy than that of metmyoglobin. These features of the heme in MnP must be favorable for the peroxidase catalytic mechanism involving oxidation of the heme iron to FeIV. Consequently, it is most likely that the heme environment of MnP resembles those of HRP, cytochrome c peroxidase, and lignin peroxidase.

Basidiomycota↗
PubMed1985

Inhibitory action of dipyrone on rat thyroid peroxidase and lactoperoxidase activities.

Previous studies have shown that phenylbutazone, another pyrazolone, inhibits thyroid peroxidase activity and interferes with iodide organification. We have developed "in vitro" studies with rat particulated peroxidase and lactoperoxidase (LPO) to study the effects of dipyrone upon thyroid peroxidase and to determine the type of inhibition. The 3-monoiodothyrosine (MIT) and 3,5-diiodothyrosine (DIT) synthesis was markedly affected by 6 X 10(-4) M dipyrone with inhibitions of 59% and 30% respectively. No difference was observed with lower concentrations. Inhibition of peroxidase activity (Triiodide assay) was found when crude rat peroxidase preparations and LPO were incubated with dipyrone in concentrations ranging from 10(-3) M to 10(-8) M, with a Ki of 2.5 X 10(-5) M and 4 X 10(-5) M respectively. Guaiacol peroxidation was scarcely affected by the action of the drug; 10(-3) M produced inhibition of 50%. Line weaver-Burk: plots were used to investigate the inhibition of LPO activity by dipyrone. The inhibition by the drug was competitive with the iodide. We may conclude that dipyrone and other drugs of the pyrazolone group act upon peroxidase activity "in vitro", by an inhibition of competitive type and in presence of iodide.

Aminopyrine↗
PubMed1987

Serine incorporation into the selenocysteine moiety of glutathione peroxidase.

The selenium in mammalian glutathione peroxidase is present as a selenocysteine ([Se]Cys) moiety incorporated into the peptide backbone 41-47 residues from the N-terminal end. To study the origin of the skeleton of the [Se]Cys moiety, we perfused isolated rat liver with 14C- or 3H-labeled amino acids for 4 h, purified the GSH peroxidase, derivatized the [Se]Cys in GSH peroxidase to carboxymethylselenocysteine ([Se]Cys(Cm)), and determined the amino acid specific activity. Perfusion with [14C]cystine resulted in [14C]cystine incorporation into GSH peroxidase without labeling [Se]Cys(Cm), indicating that cysteine is not a direct precursor for [Se]Cys. [14C]Serine perfusion labeled serine, glycine (the serine hydroxymethyltransferase product), and [Se]Cys(Cm) in purified GSH peroxidase, whereas [3-3H]serine perfusion only labeled serine and [Se]Cys(Cm), thus demonstrating that the [Se]Cys in GSH peroxidase is derived from serine. The similar specific activities of serine and [Se]Cys(Cm) strongly suggest that the precursor pool of serine used for [Se] Cys synthesis is the same or similar to the serine pool used for acylation of seryl-tRNAs.

Amino Acids↗
PubMedDate not supplied

Electron cytochemistry of peroxidase activity in neutrophils of the bone marrow of the frog Rana temporaria.

The bone marrow of the frog was studied during the spring and winter periods. During the winter period, one type of large granules in the neutrophils of the frog proved to be peroxidase-positive. The remaining, smaller granules are peroxidase-negative. In the spring, immature and mature neutrophils are encountered in the frog. The mature neutrophils of the frog in the spring and winter periods are analogous. The immature neutrophils contain peroxidase activity in the perinuclear space, the endoplasmic reticulum and some of the granules. Some of the peroxidase-containing granules are directly associated with the canals of the endoplasmic reticulum. In the immature neutrophils, during the formation of the peroxidase-containing granules, peroxidase-negative granules smaller in size are already present in the cytoplasm. Thus, the sequence of granule formation usual for mammals is apparently not observed in the neutrophils of certain amphibia. "Annular" mitochondria, encompassing part of the cytoplasm were detected in the neutrophils. These apparently represent a section through a spherical mitochondrion enveloping and isolating a certain zone of the cell. It is proposed that the mitochondria in this way, differing from the lysosomal mode, participate in the catabolism of the cytoplasm.

Animals↗
PubMed1987

Plasma selenium and glutathione peroxidase in relation to cancer, angina pectoris and short-term mortality in 68-year-old men.

Plasma selenium and plasma glutathione peroxidase were measured in 483 68-year-old men participating in a longitudinal population study, in which the probands were representatively selected. The prevalence of cancer and coronary heart disease was assessed by a structured interview. In plasma the concentration of selenium was 1.08 +/- 0.18 mumol X l-1 and the activity of glutathione peroxidase 540 +/- 90 mumol X l-1 X min-1. Plasma selenium was correlated to glutathione peroxidase activity (r = 0.49, p less than 0.001), but not significantly to plasma albumin levels (r = 0.18). Plasma selenium and glutathione peroxidase values in subjects with cancer or angina pectoris were not significantly different from those in subjects without these diseases. Plasma selenium concentration and glutathione peroxidase activity in the subjects who died within 1 year of screening were 89% and 88%, respectively, of the values among survivors (p less than 0.01). For the subjects who died during the second year after screening, these variables did not differ significantly from the values among survivors, 97% and 99%, respectively. Since the relation of low selenium and glutathione peroxidase to mortality was observed only for the first year, it was probably due to a disturbed nutritional state prior to death, rather than to a long-term negative influence of low plasma selenium on the mortality risk. Furthermore, the data have failed to demonstrate a relationship between selenium status and cancer or angina pectoris.

Aged↗
PubMedDate not supplied

[Role of peroxidase in the pathogenesis of parodontosis].

In order to study the role of peroxidase in pathogenesis of periodontosis clinical observations were carried out in 132 patients with inflammatory-dystrophic form of periodontal disease and eight species of laboratory and domestic animals were used in experiments. In the patients studied a distinct increase in peroxidase activity was observed in mixed saliva and in gum tissues, which correlated with the severity of the periodontal disease. Inflammatory-dystrophic impairment of cat periodontium was accompanied by an increase in the peroxidase activity only in gum and alveolar process tissues; cats are characterized by the highest amounts of exogenous peroxidase in oral tissues as compared with other laboratory animals. High amounts of exogenous peroxidase did not affect the periododontal tissues of rats during long-term experiments. The main protective effects of the enzyme were as follows: bacteriostatic influence on streptococci in oral cavity and inhibition of leukocyte emifration. Estimation of the peroxidase activity in saliva may be considered as a diagnostic test for periodontosis and may be used to monitore the course of treatment.

Adult↗
PubMed1985

Ultrastructure of human basophils developing in vitro. Evidence for the acquisition of peroxidase by basophils and for different effects of human and murine growth factors on human basophil and eosinophil maturation.

We examined the ultrastructure of human fetal cord blood mononuclear cells cultured in medium supplemented with supernatants of human T lymphocytes (basophil growth factor, BGF), in medium supplemented with supernatants of cloned mouse leukocytes (mast cell growth factor, MCGF) or in MCGF followed by BGF. These cultures provided the first opportunity to perform detailed morphologic and cytochemical studies of human basophilopoiesis in a nonleukemic setting. Cultures of human fetal cord blood mononuclear cells in BGF contained numerous mature basophils, which underwent a sequence of maturation similar in ultrastructure to that previously described in guinea pigs and mice. The cultures also contained variable but often substantial numbers of eosinophils. Eosinophils exhibited peroxidase activity in secretory structures (Golgi, rough endoplasmic reticulum) and cytoplasmic granules, and peroxidase-positive eosinophil granules were released into the medium by dead eosinophils. By contrast, basophils never exhibited peroxidase-positive Golgi structures or rough endoplasmic reticulum but frequently contained variable numbers of peroxidase-positive granules and occasional small cytoplasmic vesicles. Taken together, these findings suggest that basophils do not synthesize peroxidase but acquire the enzyme by the vesicular uptake of peroxidase released from eosinophils. In medium supplemented with MCGF, cells in the basophil lineage proliferated, but their maturation generally did not progress beyond the early basophilic myelocyte stage. The replacement of MCGF by BGF permitted the basophils (and eosinophils) to complete maturation, as judged by a reduction in overall cell size, increased nuclear segmentation and chromatin condensation, and cytoplasmic granule maturation. Mouse MCGF did not promote the development of mast cells in cultures of human fetal cord blood mononuclear cells, when used either alone or in series with BGF. Indeed, no mast cells were observed in any of the cultures examined in this study. Nor did we find cells with ultrastructural features intermediate between those of basophils and mast cells or with features intermediate between those of basophils and eosinophils.

Animals↗
PubMed1984

The enzyme glutathione peroxidase in arachidonic acid metabolism of human platelets.

We investigated the possible regulatory role of glutathione peroxidase on thromboxane formation by reducing peroxides in platelets. Experiments carried out in platelet lysates demonstrated that the burst of the arachidonate metabolism was accompanied by a simultaneous burst of hydrogen transfer from glutathione to peroxides, catalyzed by endogenous glutathione peroxidase. The burst of hydrogen transfer was partially inhibited by acetylsalicylate concurrently with the complete inhibition of malondialdehyde formation, thus suggesting that the hydrogen acceptor peroxides were derived in part from the cyclooxygenase pathway. Moreover, increasing glutathione peroxidase activity by adding purified enzyme to the incubation media decreases thromboxane formation. Intact platelets, stimulated with arachidonic acid or thrombin, produced malondialdehyde and thromboxane in amounts roughly inversely related to the endogenous glutathione peroxidase activity. In contrast, no correlation was observed between glutathione peroxidase activity and agonist-induced platelet aggregation. Our experiments suggest that in normal platelets, glutathione peroxidase controls thromboxane formation.

Adult↗