Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During the course of gestation, a large amount of iron is transferred rapidly and unidirectionally from mother to fetus across the placenta. It has been postulated that one of the first steps involved in placental iron transfer involves binding of the maternal transferrin-iron complex to the surface of the placenta and the subsequent removal of iron and release of transferrin back into the maternal circulation. To determine if transferrin is present on the surface of human placental villi, two different immunocytochemical methods have been used: (1) an unlabeled antibody, peroxidase-antiperoxidase (PAP) method utilizing rabbit antiserum to human transferrin, goat anti-rabbit IgG and rabbit peroxidase-antiperoxidase complex or; (2) a peroxidase-labeled antibody method utilizing goat antiserum to human transferrin and peroxidase-conjugated rabbit anti-goat IgG. The peroxide was then localized by incubation in a diaminobenzidine-hydrogen peroxide medium. Examination of the tissue in the electron microscope revealed the reaction product deposited as discrete patches or particles on the microvillous surface of human syncytial trophoblast. Controls using non-immune serum or an antiserum adsorbed with purified human transferrin showed no reaction product on the surface. The results provide morphological confirmation for the presence of transferrin on the surface of human syncytial trophoblast lining the maternal blood spaces.
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PMID:Localization of transferrin on the surface of the human placenta by electron microscopic immunocytochemistry. 79 Oct 6

The peripheral blood of an acute myelomonocytic leukemia patient has been cultured for 16 months. The culture is at present at the 140th population doupling level. The cultured cells have the characteristics of so-called lymphoblastoid cells and proliferate actively as individual cells in small clusters, or in large clumps consisting of large mononuclear cells. Some of these cells appeare to be lymphoid, but the majority are immature mononuclear cells with a tendency to lobulate. They gave a weakly positive peroxidase reaction at the beginning of cultivation, and have given a strongly positive esterase reaction persistently. The cytoplasm shows ciliary or tail-like projections as the cell matures. Complement (C3) receptor and IgG receptors are found on the cell surface, and active phagocytosis is mannifest. Colloidal iron particles or viable red blood cells attached to the cell membrane suggesting possible differentiation to reticulum cells or macrophages. The cultured cells are mostly diploid but some cells show chromosome abnormality. Herpes type virus was foun in the nucleus, cytoplasma and on the cell membrane. The transplanatation of cultured cells to the cheek pouch of hamsters produced small tumors with histological findings resembling reticulum cell sarcoma.
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PMID:Characteristics of hematopoietic cell line established from human myelomonocytic leukemia. 82 70

Erythrocytic glutathione-peroxidase (GSH-Px) activity and plasma selenium concentrations were measured in 14 patients: 7 with iron deficiency and 7 with raised serum iron levels. The decreased enzymatic activity in iron deficiency was confirmed. Plasma selenium was significantly lower in patients with lower serum iron; furthermore there is a significant correlation between serum iron and plasma selenium concentrations. Another correlation even more significant was found between plasma selenium and enzyme activity in all the cases we studied. These data suggests that the importance of iron for GSH-Px activity may be merely due to its relationship with selenium and that plasma selenium concentration may be of critical importance for enzyme activity.
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PMID:Erythrocytic glutathione peroxidase: its relationship to plasma selenium in man. 88 36

The electron-dense tracers ferritin, and iron-dextran, and the protein horseradish peroxidase, have been used to investigate the ultrastructural basis of permeability in the upper and lower segments of the Malpighian tubules of Glomeris marginata. All these materials were able to cross the basal lamina and enter the tubule lumen of the upper segment, and it was established that horseradish peroxidase was able to enter the channels which interrupt the apical junctions. In the upper segment, ferritin, iron-dextran, and horseradish peroxidase are taken up and accumulated within intracellular vesicles. In the lower segment ferritin and iron-dextran enter the cells but become generally distributed over the cytoplasm, as well as entering membrane-bounded vacoules. The behaviour of horseradish peroxidase could not be assessed by owing to the presence of endogenous peroxidase activity in the cells. After fixation by direct application of glutaraldehyde to the undissected tubules, the extracellular spaces contained large numbers of membrane-bounded vesicles. The significance of these observations is discussed in relation to the physiological activities of the tubules.
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PMID:Ultrastructural tracer studies on the permeability of the Malpighian tubule of the pill millipede, Glomeris marginate (Villers). 92 20

Resonance Raman spectra of oxidized hydroperoxidases are examined for shifts in the structure-sensitive, anomalously polarized bands; these are found, respectively, at 1576, 1567 and 1570 cm-1 in the high-spin resting enzymes: horse radish peroxidase, horse blood catalase, and cytochrome c peroxidase. In compound II of horse radish peroxidase and horse blood catalase, and in the enzyme-substrate complex of cytochrome c peroxidase, this band appears at 1587-1590 cm-1 and indicates the iron atom is now in-plane with the porphyrin ring. Weak Raman scattering found with horse radish peroxidase I is consistant with a porphyrin eta-cation radical formulation.
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PMID:Laser Raman spectra of oxidized hydroperoxidases. 94 50

The red cell glutathione-peroxidase (GSH-Px) activity of 9 normal subjects is compared with that of 15 cases of iron deficiency anaemia and with 13 cases of heterozygous beta-thalassemia with the same degree of anaemia and hypochromia. 2 cases of sideroblastic anaemia with high serum iron levels were also examined. Enzymatic activity was found to be significantly decreased in iron deficiency anaemia (about 55% of normal range), while it was not affected in heterozygous beta thalassaemia and it was increased in the 2 cases of sideroblastic anaemia. Moreover, GSH-Px activity exhibited a significant correlation with serum iron levels in all the patients studied. The observed modifications in GSH-Px activity are not correlated with erythrocyte ageing because reticulocyte-poor fractions exhibited GSH-Px activity which was not significantly reduced in respect of the reticulocyte-rich ones. These data seem to suggest that iron has a crucial connection with erythrocyte GSH-Px and that the enzyme deficiency may be of some importance in explaining the decreased red cell survival observed in severe iron-deficiency anaemias.
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PMID:Plasma iron and erythrocytic glutathione peroxidase activity. A possible mechanism for oxidative haemolysis in iron deficiency anemia. 96 43

Complex carbohydrates and cations have been localized by cytochemical methods in mitochondria of mammalian leukocytes, hepatocytes and oyster gill epithelium. Glycoconjugate of acidic nature was visualized with the dialyzed iron method in or on the outer membrane and inner boundary membrane and in the outer intermembrane space but not on the membranes of cristae or in the intracristate space, or matrix. Sulfated glycoconjugate was demonstrated with the high iron diamine method in a similar distribution and in, on, or between, membranes of cristae as well. Intermittent aggregates of dialyzed iron and high iron diamine stained material were often found in the outer intermembrane space. The periphery of isolated rat liver mitochondria also stained with a Concanavalin A horseradish peroxidase technique, indicating the presence of macromolecules, presumably glycoproteins containing mannose or glucose. The distribution of antimonate reactive cation in mitochondria of leukocytes resembled that of the acidic glycoconjugate, indicating binding of cations to anionic groups of the latter. The complex carbohydrates and cations demonstrated cytochemically in mitochondria are considered in relation to previous biochemical studies.
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PMID:Cytochemical localization of glycoconjugate in mitochondria. 100 72

The carbohydrate rich filamentous coat investing the mature Schistosoma manosini cercaria affects important physiological and antigenic properties of the larval body surface. The origin of the filamentous coat and intrinsic topochemical properties of ccrcariae were investigated by fine structural and cytochemical examination of intrasporocyst larvae of various developmental stages. Staining results achieved with concanavalin A-peroxidase, bismuth subnitrate, silver protein, cationic colloidal iron, and polycationic ferritin indicate the presence of both neutral and acidic glycans at the external surface of the trilaminar tegumental plasmalemma, the latter saccharide moieties conferring upon this surface a superficial electronegative charge. The filamentous coat, apparent only on relatively well-developed larvae, is rich in neutral glycans, but fails to stain with cationic cytochemical reagents. Appearance of the surface coat occurs coincident with the differentiation of tegumentary cytons, the elaboration of carbohydrate-containing vesicles by Golgi complexes within these cell bodies, and the translocation of vesicles from sites of formation to the tegumental syncytium. It is likely that those saccharides, glycoproteins, and/or glycolipids present within the neutral filamentous coat, and those which constitute the acidic layer immediately superticial to the larval body surface, are intrinsic molecular constituents of the cercarial tegumental plasmalemma. Both the neutral filamentous coat and subjacent acidic layer may be regarded as distinct functional elements of the larval body surface glycocalyx. The molecular architecture of this membrane complex apparently reflects the specializations necessary for survival in fresh water followed by rapid adaptation to the serum environment of the mammalian host.
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PMID:Schistosoma mansoni: topochemical features of intrasporocyst cercariae. 100 81

Treatment of living entamoeba histolytica cells with low concentrations of concanavalin A (con A) and peroxidase results in redistribution of the plasma membrane con A receptors to one pole of the cell where a morphologically distinct region--the uroid--is formed. Capping of con A receptors is not accompanied by parallel accumulation of ruthenium red-stainable components. In capped cells, the pattern of distribution of acidic sites ionized at pH 1.8 (labeled by colloidal iron) at the outer surface and of membrane particles (integral membrane components revealed by freeze-fracture) is not altered over the uroid region. Cytochemistry of substrate-attached microexudate located in regions adjacent to E. histolytica cells demonstrates the presence of con A binding sites and ruthenium red- and alcian blue-stainable components and the absent of colloidal iron binding sites. In a previous report we demonstrated that glycerol-induced aggregation of the plasma membrane particles is accompanied by a discontinuous distribution of colloidal iron binding sites, while con A receptors and acidic sites ionized at pH 4.0 remain uniformly distributed over the cell surface. Taken together, our experiments show that, in E. histolytica cells, peripheral membrane components may move independently of integral components and, also, that certain surface determinants may redistribute independently of others. These results point to the complexity of the membrane structure-cell surface relationship in E. histolytica plasma membranes relative to the membrane of the erythrocyte ghost where integral components (the membrane-intercalated particles) contain all antigens, receptors, and anionic sites labeled so far. We conclude that fluidity of integral membrane components (integral membrane fluidity) cannot be inferred from the demonstration of the mobility of surface components nor, conversely, can the fluidity of peripheral membrane components (peripheral membrane fluidity) be assumed from demonstration of the mobility of integral membrane components.
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PMID:Membrane structure and surface coat of Entamoeba histolytica. Topochemistry and dynamics of the cell surface: cap formation and microexudate. 115 Jul 44

1. Metabolism of added hydroperoxides was studied in hemoglobin-free perfused rat liver and in isolated rat hepatocytes as well as microsomal and mitochondrial fractions. 2. Perfused liver is capable of removing organic hydroperoxides [cumene and tert-butyl hydroperoxide] at rates up to 3--4 mumol X min-1 X gram liver-1. Concomitantly, there is a release of glutathione disulfide (GSSG) into the extracellular space in a relationship approx. linear with hydroperoxide infusion rates. About 30 nmol GSSG are released per mumol hydroperoxide added per min per gram liver. GSSG release is interpreted to indicate GSH peroxidase activity. 3. GSSG release is observed also with added H2O2. At rates of H2O2 infusion of about 1.5 mumol X min-1 X gram liver-1 a maximum of GSSG release is attained which, however, can be increased by inhibition of catalase with 3-amino-1,2,4-aminotriazole. 4. A contribution of the endoplasmic reticulum in addition to glutathione peroxidase in organic hydroperoxide removal is demonstrated (a) by comparison of perfused livers from untreated and phenobarbital-pretreated rats and (b) in isolated microsomal fractions, and a possible involvement of reactive iron species (e.g. cytochrome P-450-linked peroxidase activity) is discussed. 5. Hydroperoxide addition to microsomes leads to rapid and substantial lipid peroxidation as evidenced by formation of thiobarbituric-acid-reactive material (presumably malondialdehyde) and by O2 uptake. Like in other types of induction of lipid peroxidation, malondialdehyde/O2 ratios of 1/20 are observed. Cumene hydroperoxide (0.6 mM) gives rise to 4-fold higher rates of malondialdehyde formation than tert-butyl hydroperoxide (1 mM). Ethylenediamine tetraacetate does not inhibit this type of lipid peroxidation. 6. Lipid peroxidation in isolated hepatocytes upon hydroperoxide addition is much lower than in isolated microsomes or mitochondria, consistent with the presence of effective hydroperoxide-reducing systems. However, when NADPH is oxidized to the maximal extent as evidenced by dual-wavelength spectrophotometry, lipid peroxidation occurs at large amounts. 7. A dependence of hydroperoxide removal rates upon flux through the pentose phosphate pathway is suggested by a stimulatory effect of glucose in hepatocytes from fasted rats and by an increased rate of 14CO2 release from [1-14C]glucose during hydroperoxide metabolism in perfused liver.
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PMID:Hydroperoxide-metabolizing systems in rat liver. 117 55


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