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)

Human lung adenocarcinoma sub-cell lines HAL-8, HAL-24 and HAL-33, showing different lung colonization potential (LCP), were established from human lung adenocarcinoma cell line KUM-LK-2 using repeated cloning with limiting dilution technique. Cell lines HAL-8 and -33 were characterized by high and low LCP, respectively, while HAL-24 did not give rise to lung colonies. The cell surface protein and carbohydrate profiles were determined by cell surface labeling (with lactoperoxidase-dependent 125I-iodination and galactose oxidase-NaB3H4, respectively) followed by SDS-gel electrophoresis. Various carbohydrate epitopes expressed at the cell surface were analysed by cytofluorometry using various monoclonal antibodies (MAbs) directed to Le(x), sialosyl-Le(x), sialosyl dimeric Le(x), T, Tn and sialosyl-Tn structures, which are often reported as being highly expressed in a variety of human cancers, particularly adenocarcinoma. Expression of sialosyl dimeric Le(x) (defined by MAb FH6) was high on HAL-8, moderate on HAL-33, and relatively low on HAL-24. In contrast, each of the three lines showed essentially equal expression (as determined by MAb reactivity) of sialosyl-Tn (defined by MAb TKH2), Le(x) (defined by MAb SH1), and Tn (defined by MAb 1E3). The cell lines showed extremely weak expression of T (defined by MAb HH8). LCP of HAL-8 and -33 was completely inhibited by sialidase treatment of cells. It is suggested that higher expression of sialosyl dimeric Le(x) (defined by MAb FH6) in HAL-8 cells may play an important role in higher potential of blood-borne lung colonization.
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PMID:Human lung adenocarcinoma cell lines with different lung colonization potential (LCP), and a correlation between expression of sialosyl dimeric Le(x) (defined by MAb FH6) and LCP. 167 53

A multi-coupled enzyme assay system for determining sialidase activity is described. Enzymes, substrates and chromogens are reacted in situ and determined spectrophotometrically in ELISA microtiter plates. Sialidase is assayed by the extent of desialylated galactose on an appropriate sialoglycoconjugate (fetuin), which is otherwise unavailable for oxidation by galactose oxidase. The oxidation is monitored by the coupling of H2O2 released to a third enzyme, peroxidase. The rate of change of absorbance at 405 nm, resulting from the oxidized chromogen is a measure of the reaction rate of the coupled enzyme system. A similar system can be used for determining galactose oxidase in solution, or on blots using galactose as substrate. Due to the small-scale single-step measurement, the described assay is a sensitive, convenient, and inexpensive alternative to the classic colorimetric determination.
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PMID:A coupled enzyme assay for measurement of sialidase activity. 170 71

Thirty-four cases of carcinoma of the human large intestine were studied employing a battery of histochemical techniques to identify and characterize mucosubstances, including galactose oxidase-Schiff (GOS) reaction and stainings with horseradish peroxidase-labeled lectins. The results disclosed that the goblet cell-type mucin (GCM) of the left colon differed from that of the right colon in containing 8-O-acetylated N-acetylneuraminic acid (NANA) more abundantly and 8-O-acetylated NANA-(alpha Fuc)-beta Gal type terminal structures. The right colonic GCM, on the other hand, was shown to contain alpha Fuc-beta Gal type predominantly. Surface coat-type mucin (SCM) showed consistent histochemical reactivities regardless of the sites in the large intestine. The transitional mucosa surrounding carcinoma tissues characteristically revealed decreased sulfation and neuraminidase-induced GOS reactivity, suggesting the presence of NANA-beta Gal type terminals. The carcinoma tissues resembled the transitional mucosa in showing neuraminidase-induced GOS reactivity, but differed from the latter in possessing intense UEA-I reactivity. The present study indicated that the refined histochemical techniques recently developed were quite useful for understanding the histochemical reactivities correlating with sugar structures.
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PMID:Mucosubstance histochemistry of the normal mucosa and carcinoma of the large intestine. Galactose oxidase-Schiff reaction and lectin stainings. 241 24

Washed ejaculated human spermatozoa were surface labelled with 125I, using solid phase (iodogen) or enzymic (lactoperoxidase) methods, while membrane components possessing terminal galactose or galactosamine residues were labelled with the galactose oxidase-sodium [3H]borohydride technique. All three procedures revealed the presence of 2 major labelled surface components. The first comprised a broad band of radioactivity migrating just behind the ion front on SDS-PAGE, which could be extracted with chloroform and methanol, suggesting a lipid-like composition. The second fraction exhibited properties consistent with a major glycoprotein component of the human sperm plasma membrane, giving a peak of radioactivity with Mr = 20,000, within which a discrete doublet of bands (Mr = 17,000 and 19,000) could be resolved by autoradiography. A more detailed analysis of the labelled protein fraction after TCA precipitation revealed a number of other surface components, the major ones of which exhibited Mr values of 30,000, 45,000, 66,000, 115,000 and 160,000. Western blot analysis was then used to determine whether any of the surface components described above interacted with the gamma-globulin fraction of antisera obtained from patients exhibiting idiopathic autoimmunity against sperm antigens. Using a purified membrane preparation as the target, antibodies were detected against numerous high molecular weight bands with Mr values similar to the major components of the human sperm surface (35,000, 45,000, 66,000, 90,000 and 150,000). The nature of the antigens targeted by these antisera did not correlate with the ability of the latter to stimulate or suppress sperm-oocyte fusion.
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PMID:Analysis of the surface labelling characteristics of human spermatozoa and the interaction with anti-sperm antibodies. 244 96

Secretory products of granular and mucous cells in the gill epithelium of the carp, Cyprinus carpio, were distinguished by their cytochemical reactions with peroxidase-labelled lectins and with the galactose oxidase (GO)-Schiff reagents. Secretory products of granular cells reacted with lectins from Triticum vulgaris (WGA), Arachis hypogaea (PNA), Dolichos biflorus (DBA), Glycine max (SAB), and Lotus tetragonolobus (LTA). They also reacted with GO-Schiff reagents. After sialic acid cleavage with HCl, new binding sites for DBA and SBA appeared, suggesting the terminal sequence sialic acid-N-acetylgalactosamine (SA-GalNAc) for the secretion of this cell type. In mucous cells, binding sites for WGA, DBA, and SBA and, after acid hydrolysis, binding sites for PNA and a positive GO-Schiff reaction were detected. The terminal trisaccharide sialic acid-galactose (beta 1-3)-N-acetylgalactosamine (SA-Gal-GalNAc) is proposed for the secretion of mucous cells. These cytochemical differences are discussed in light of the involvement of both cell types in fish mucus elaboration.
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PMID:Light microscopic characterization of glycoconjugates in secretory cells of the carp (Cyprinus carpio) gill epithelium. 244 6

The apical surface coat of type II pneumocytes and Clara cells in pre- and post-natal rat lung was examined with lectin histochemical methods. Lectins from Helix pomatia (HPA), peanut (PNA) and Maclura pomifera (MPA) were conjugated with horseradish peroxidase and used to stain paraffin sections of fixed lung with or without certain pre-treatments. HPA and MPA were observed to react with almost all type II pneumocytes at postnatal day 1. Type II pneumocytes that stained with a sialidase-PNA sequence increased from a few positive cells at postnatal day 5 to many in the adult. It has been reported that the surface coat of type II pneumocytes closely resembles that of Clara cells in its staining with histochemical methods employing cationic dyes or lectins including MPA and PNA. However, staining with HPA, especially after periodic acid oxidation, revealed many type II pneumocytes with strong reactivity but showed only a few Clara cells that were faintly positive. HPA also stained alveolar macrophages. The HPA affinity of macrophages, however, was labile to oxidation with periodic acid or galactose oxidase unlike that of type II pneumocytes. This difference suggests that HPA recognizes more than one type of sugar structure.
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PMID:Comparison of glycoconjugates at the surface of developing type II pneumocytes and Clara cells. 277 37

Plasma membranes from chick embryo neuronal primary cultures were isolated after subjecting 5-day-old cells, previously surface labeled with either lactoperoxidase-catalyzed radioiodination or galactose oxidase/NaB3H4, to a freeze-thaw cycle. The cellular material adhering to the culture substratum was washed, and the "wash" fractions were pooled and centrifuged at 37,000g. The resulting pellet was resuspended in 3 ml of buffer, layered on 33 ml of 33% sucrose, and centrifuged at 105,000g. Radioactivity was recovered at the top of the gradient. Sedimentation of these fractions and biochemical studies revealed that the pellet was 20- and 12-fold enriched in (Na+,K+)-adenosinetriphosphatase and 5'-nucleotidase, respectively. The preparation was devoid of inner mitochondrial (succinate dehydrogenase), outer mitochondrial (monoamine oxidase), endoplasmic reticulum (glucose-6-phosphatase), outer mitochondrial (monoamine oxidase), endoplasmic reticulum (glucose-6-phosphatase), and Golgi (UDP galactose:N-acetylglucosamine galactosyltransferase) enzymatic markers. Ultrastructural studies showed that the membrane preparation was homogeneous and lacked mitochondria endoplasmic reticulum and lysosomes. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate showed the presence of 11 protein components with molecular masses ranging from 120 to 300 kDa. This method for the isolation of plasma membranes probably depends on the capacity of the cellular material to adhere to the culture substratum and to entrap intracellular organelles during the freeze-thaw cycle. The membrane preparation seems suitable for studying the function of high-molecular-weight protein components of neuronal plasma membranes.
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PMID:Isolation of plasma membranes from neurons grown in primary culture. 282 51

In human pancreas, soybean agglutinin (SBA) conjugated to horseradish peroxidase reacted with the acinar cells secreting blood group A and/or H antigen, but not with those secreting only B antigen. For detailed histochemical characterization of SBA staining, the effects of treatment with unlabeled lectins and of digestion of certain enzymes on SBA staining were investigated in formalin-fixed, paraffin-embedded pancreatic tissue from individuals of different blood groups. Pre-incubation of sections with unlabeled Dolichos biflorus agglutinin to block A antigen eliminated subsequent SBA staining in the cells secreting A antigen, although failing to induce any effects in those secreting H antigen. In contrast, pre-incubation with unlabeled Ulex europaeus agglutinin-I (UEA-I) to block H antigen abolished SBA staining in cells secreting H antigen but not in those secreting A antigen. Treatment with galactose oxidase yielded the same results as those with unlabeled UEA-I, i.e., SBA reactivity was significantly diminished in cells secreting H antigen but not in those secreting A antigen. Digestion with beta-galactosidase resulted in a slight decrease of SBA staining in the cells secreting H antigen. Accompanying the decrease of SBA staining, reactivity with Griffonia simplicifolia agglutinin-II (GSA-II) appeared for the first time in the enzyme-susceptible, SBA-reactive cells secreting H antigen. Pre-treatment with galactose oxidase abolished this effect of beta-galactosidase. The GSA-II reactivity disclosed by treatment with galactosidase was completely eliminated by digestion with beta-N-acetylhexosaminidase, indicating that GSA-II staining after digestion with galactosidase is due to exposed penultimate beta-N-acetyl-D-glucosamine residues. These results demonstrate that at least two substances react with SBA in acinar cells of human pancreas, one being terminal beta-N-acetyl-D-galactosamine residues of A antigen, and the other being terminal beta-D-galactose-(1----3 or 1----4)-beta-N-acetyl-D-glucosamine dimers in the precursor of blood group H antigen. Such dimers may exist in close proximity to L-fucose residues of H antigen, since unlabeled UEA-I blocked SBA staining.
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PMID:Histochemical reactivity of soybean agglutinin with blood group antigens and their precursor substances in acinar cells of human pancreas. 295 34

We have isolated a heme protein from canine midbrains that possesses potent peroxidase activity. This enzyme catalyzes the oxidation of dopamine to neuromelanin in the presence of H2O2. We have further shown that the isolated peroxidase possesses potent cytotoxic activity in the presence of superoxide or H2O2 and Cl-. The enzyme possesses an endogenous NAD(P)H oxidase activity that can promote the cytotoxic activity by virtue of its production of superoxide. Other enzymes such as dihydroorotate dehydrogenase and galactose oxidase, which produce O2- and H2O2, respectively, are also effective in promoting the cytotoxic activity of the brainstem peroxidase. Although rat erythrocytes were routinely used as the target cell, other cell types, including rat hepatoma and mouse neuroblastoma cells, are also susceptible to the toxic action of the peroxidase. The cytotoxic action of the brainstem peroxidase is dramatically enhanced by kainic acid and is significantly enhanced by Mn2+, whereas dopamine was found to be a potent inhibitor of the cytotoxic activity. Based on these findings, we postulate a central role for the brainstem peroxidase in dopamine metabolism as well as in the biochemical and anatomical changes associated with Parkinson's disease.
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PMID:Neuromelanogenic and cytotoxic properties of canine brainstem peroxidase. 302 61

Phagocytosis is a critical host defense mechanism of neutrophils. In this study, membrane protein changes occurring during phagocytosis were studied in human neutrophils using surface radiolabeling before or after phagocytosis of various target particles. Cells were labeled at the cell surface using lactoperoxidase-catalyzed iodination or neuraminidase-galactose oxidase-NaB3H4, galactose oxidase-NaB3H4, or periodate-NaB3H4 techniques. Such studies are complicated by the fact that these techniques identify many surface proteins on the phagocyte, and labeling after phagocytosis occurs often results in radiolabeling proteins of the target particle, thus making changes in cell-surface proteins more difficult to detect. Immunoprecipitation with monoclonal antibody AHN-1, which reacts with a carbohydrate present on several human neutrophil surface proteins and inhibits phagocytosis, eliminated interference caused by radiolabeled proteins of the target particle and simplified analysis by restricting the study to a limited number of proteins. AHN-1 immunoprecipitated less radiolabeled protein from neutrophils labeled after phagocytosis of particles opsonized with IgG or complement than from cells labeled before phagocytosis. Isolation of phagocytic vesicles containing opsonized emulsified paraffin oil demonstrated that three proteins of mol wt 105,000, 140,000, and 170,000 recognized by AHN-1 were internalized in the phagocytic vesicle during phagocytosis.
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PMID:Changes in neutrophil surface protein composition accompany phagocytosis. 303 79


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