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)

Platelets and megakaryocytes from 11 patients with the carcinoid syndrome have been studied by transmission electron microscopy. Cells fixed in phosphate-buffered glutaraldehyde are oval to discoid, with pseudopods, a dilated open-channel system, and a prominent dense tubular system as defined by peroxidase activity and alkaline bismuth stain. Atypical with hexagonal lattices and treaded substructures and large (diameter greater than 0.5 mum), phosphatase-positive, debris-containing vacuoles are four times more numerous than in normal platelets. Incubation of platelets in a 0.05% suspension of latex results in particle incorporation into phagosomes and the debris-containing vacuoles. Molybdate-dichromate stain reveals two classes of dense bodies, one of which (with a reticular core) is 20 times more numerous than in normal platelets. Bone marrow megakaryocytes lack both dense bodies and debris vacuoles analogous to those found in circulating platelets. These results suggest autophagy or endocytosis abnormalities and provide evidence for multiple types of dense bodies in carcinoid platelets.
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PMID:Ultrastructural cytochemistry of platelets and megakaryocytes in the carcinoid syndrome. 18 65

The molybdenum requirement for growth and conidial formation by Aspergillus flavus, A. terreus, and A. sulphureus was found to be 0.2 ppb, which was one-fifth that of an A. niger isolate. Molybdenum deficiency depressed growth, conidial formation, dry weight, soluble protein, and the specific activities of nitrate reductase, succinic dehydrogenase, and aconitase in all the isolates of Aspergillus studied, but the specific activities of catalase and peroxidase were depressed only in isolates of A. niger, A. terreus, and A. flavus. Also, molybdenum deficiency stimulated the specific activities of acid phosphatase and ribonuclease in the A. flavus isolate, although the specific activities of these enzymes decreased in other isolates. Eighteen hours after the addition of molybdenum (5 ppb) to molybdenum-deficient (0.02 ppb) cultures of A. niger, the specific activities of catalase, peroxidase and succinic dehydrogenase were restored in the absence of cycloheximide, while the specific activity of nitrate reductase was recovered even in the presence of the inhibitor. There was no effect on the specific activities of aconitase and acid phosphatase following the addition of molybdenum to molybdenum-deficient cultures of A. niger.
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PMID:Molybdenum nutrition of isolates of four Aspergillus species. 309 Dec 28

The performance of an enzymatic colorimetric method for the determination of inorganic phosphorus in serum and urine is described. Phosphate ions react with inosine in the presence of purine nucleoside phosphorylase to form hypoxanthine; this is oxidized by xanthine oxidase to uric acid with production of hydrogen peroxide. The latter is determined with the aid of the chromogen system peroxidase/4-aminophenazone/N-ethyl-N-(3-methylphenyl)-N'-acetylethyl enediamine , the coloured product being measured at 555 nm. This series of reactions is completed in 5 min at 37 degrees C. The test is linear up to 240 mg/l. Analytical recovery in serum averaged 101.2 +/- 1.2% and in urine 101.9 +/- 3.2%. Within-run and between-run precision studies in serum and urine samples gave CVs less than or equal to 4.54% (at 22.0 mg/l). Results obtained by this method agree (r = greater than or equal to 0.983) with the molybdate UV and molybdenum blue methods. Interference by endogenous substances, including organic phosphate, was negligible.
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PMID:Enzymatic colorimetric method for the determination of inorganic phosphorus in serum and urine. 313 8

Phenylalanine hydroxylase was prepared from rat liver and purified 200-fold to about 90% purity. All the enzymic activity of the liver appeared in a single protein of mol.wt. approx. 110000, but omission of dithiothreitol and of a preliminary filtration step to remove lipids resulted in partial conversion into a second enzymically active protein of mol.wt. approx. 250000. The K(m) and V(max.) values of the enzyme for phenylalanine, p-fluorophenylalanine and dimethyltetrahydropterin were measured; p-chlorophenylalanine inhibited the enzyme by competing with phenylalanine. Disc gel electrophoresis at pH7.2 showed a single protein band containing all the enzymic activity, but at pH8.7 the enzyme dissociated into two inactive fragments of similar but not identical molecular weight. The molecule of phenylalanine hydroxylase contained two atoms of iron, one atom of copper and one molecule of FAD; molybdenum was absent. Treatment with chelating agents showed that both non-haem iron and copper were necessary for enzymic activity. The molecule contained five thiol groups, and thiol-binding reagents inhibited the enzyme. Catalase or peroxidase enhanced enzymic activity fivefold; it is postulated that catalase (or other peroxidase) plays a part in the hydroxylation reaction independent of the protection by catalase of enzyme and cofactor from inactivation by a hydroperoxide.
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PMID:The isolation and properties of phenylalanine hydroxylase from rat liver. 485 20

A human lymphocyte culture protocol was used to identify the biocompatibility pattern of fine particulate ultra-high molecular weight polyethylene. Polyethylene did not cause an increase in lymphocyte DNA synthesis as assessed by the 3H-thymidine incorporation method on culture Days 1, 3, nor 5. As analyzed with monoclonal activation markers, the polyethylene dependent expression of major histocompatibility complex (MHC) class II antigen as well as interleukin-2 receptor (CD25) was virtually nonexistent. An apparent increase in the amount of CD11b positive monocytes/macrophages from 7% +/- 2% to 22% +/- 6% was recorded. Samples of pseudocapsules of the totally replaced hips (THR) obtained at revision operations for aseptic loosening of cementless prostheses with polyethylene lining of the acetabular component, were obtained from ten patients for immunopathologic studies. In seven cases the prostheses consisted of chromium-cobalt-molybdenum steel alloy and in three cases of titanium. Revisions were performed on average 4.6 years (range, 2.5-7) after insertion of the prostheses. The predominant cell in the lining cell layer of the periprosthetic cavity was in each case the CD11b, CD68, and nonspecific esterase positive but endogenous peroxidase-negative macrophage. Proline 4-hydroxylase positive fibroblasts dominated the stroma that was also inhabited by usually perivascular mononuclear cell infiltrations of mainly CD11b/CD68 phenotype with occasional CD4-positive cells. Only few mononuclear cells were activated CD25 positive T cells or CD19-positive B-lymphocytes. In titanium-based THRs, the cytoplasm of the macrophages contained a large number of small metallic particles, although this phenomenon was not seen in chromium-cobalt-molybdenum steel-based THRs. Fine particulate ultra-high molecular weight polyethylene is immunologically relatively insert. Nevertheless, it causes a clear foreign body type of phenomenon in vitro. The loosening of cementless acetabular components was associated with CD11b- and CD68-positive macrophage reaction in the pseudocapsular tissue. In any case, there is no clinical or experimental evidence to suggest that the use of cementless THR prostheses with polyethylene sockets would prevent an adverse biologic host response.
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PMID:Biocompatibility of polyethylene and host response to loosening of cementless total hip replacement. 824 16

We have constructed an automatic phosphate ion sensing system for the quality control of drinking water. The analyte was detected using the phosphate ion-dependent pyruvate oxidase reaction and the hydrogen peroxide produced was detected by luminol chemiluminescence catalyzed by Arthromyces ramosus peroxidase. We obtained a detection limit of 0.16 microM phosphate ion (5 ppb phosphorus) and it was possible to detect 0.32 microM phosphate ion for 48 days using pyruvate oxidase immobilized on Chitopearl BCW-2601 beads. An excellent correlation (r2 = 1.00) was obtained between the results obtained using our phosphate ion sensor and those using a modified Molybdenum Blue method.
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PMID:A chemiluminescent FIA biosensor for phosphate ion monitoring using pyruvate oxidase. 945 87

Effects of molybdenum (Mo) on antioxidative defense system and membrane lipid peroxidation in leaves of winter wheat (Triticum aestivum H. var. Huamai 8) were investigated under low temperature stress. Results of experiments indicate that Mo application in winter wheat induced a dramatic decrease in electrolyte leakage and malondialdehyde content under low temperature stress. The activities of antioxidative enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POX, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.6) were increased by Mo application and the extents of increase at low temperature were higher than those at normal temperature. Mo application also caused a significant increase in the ascorbic acid (AsA) and proline contents both at normal and low temperature and following the low temperature stress the increases in ascorbic acid and proline contents in Mo-treated winter wheat were higher. There was no significant difference in carotenoid (CAR) content between with and without Mo treatment under normal temperature, while there was a significant increase in Mo treatment under low temperature stress. It could be speculated that Mo application enhanced cold resistance by increasing the capacity to scavenge active oxygen species and alleviating membrane damage in winter wheat under low temperature stress.
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PMID:Effects of molybdenum on antioxidative defense system and membrane lipid peroxidation in winter wheat under low temperature stress. 1662 16

Serum, plasma, or urine samples are usually used for the measurement of the trace elements copper; zinc, iron, selenium, because these samples are easy to obtain; however; these samples are not always appropriate. For example, it is not possible to measure molybdenum, the major antagonist of copper; in blood or urine. Therefore measurement of trace elements in liver tissue is considered the gold standard. For the assessment of selenium the method of choice remains determination of glutathion peroxidase in erythrocytes and for the assessment of magnesium determination of magnesium in urine. We determined the accuracy and repeatability of measuring trace elements in liver biopsies and whole liver homogenates. The levels of trace elements measured were similar in both preparations (92% agreement). Liver biopsy in live animals is a relatively simple procedure but not common in The Netherlands. Reference levels of trace elements, classified as too low, low, adequate, high, and too high, were established on the basis of our research and information in the literature. In a second study we investigated the practical aspects of obtaining liver tissue samples and their use. Samples were collected from cattle on a commercial dairy farm. Liver biopsy provided additional information to that obtained from serum and urine samples. We prepared a biopsy protocol and a test package, which we tested on 14 farms where an imbalance of trace minerals was suspected. Biopsy samples taken from 4 to 6 animals revealed extreme levels of trace elements.
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PMID:[Measurement of the status of trace elements in cattle using liver biopsy samples]. 1732 2

Drought is a major environmental stress factor that affects growth and development of plants. Abscisic acid (ABA), osmotically active compounds, and synthesis of specific proteins, such as proteins that scavenge oxygen radicals, are crucial for plants to adapt to water deficit. LOS5/ABA3 (LOS5) encodes molybdenum-cofactor sulfurase, which is a key regulator of ABA biosynthesis. We overexpressed LOS5 in tobacco using Agrobacterium-mediated transformation. Detached leaves of LOS5-overexpressing seedlings showed lower transpirational water loss than that of nontransgenic seedlings in the same period under normal conditions. When subjected to water-deficit stress, transgenic plants showed less wilting, maintained higher water content and better cellular membrane integrity, accumulated higher quantities of ABA and proline, and exhibited higher activities of antioxidant enzymes, i.e., superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, as compared with control plants. Furthermore, LOS5-overexpressing plants treated with 30% polyethylene glycol showed similar performance in cellular membrane protection, ABA and proline accumulation, and activities of catalase and peroxidase to those under drought stress. Thus, overexpression of LOS5 in transgenic tobacco can enhance drought tolerance.
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PMID:Arabidopsis LOS5/ABA3 overexpression in transgenic tobacco (Nicotiana tabacum cv. Xanthi-nc) results in enhanced drought tolerance. 2188 46

Drought is the major environmental stress that limits cotton (Gossypium hirsutum L.) production worldwide. LOS5/ABA3 (LOS5) encodes a molybdenum co-factor and is essential for activating aldehyde oxidase, which is involved in abscisic acid (ABA) biosynthesis. In this study, a LOS5 cDNA of Arabidopsis thaliana was overexpressed in cotton cultivar Zhongmiansuo35 (Z35) by Agrobacterium tumefaciens-mediated transformation. The transformation and overexpression of AtLOS5 were assessed by PCR and RT-PCR analysis. Detached shoots of transgenic cotton showed slower transpirational water loss than those of Z35. When pot-grown 6-week-old seedlings were withheld from watering for 3 d, transgenic cotton accumulated 25% more endogenous ABA and about 20% more proline than Z35 plants. The transgenic plants also showed increased expression of some drought-responding genes such as P5CS and RD22, and enhanced activity of antioxidant enzymes such as superoxide dismutase, peroxidase, and ascorbate peroxidase. Their membrane integrity was considerably improved under water stress, as indicated by reduced malondialdehyde content and electrolyte leakage relative to control plants. When the pot-grown plants were subjected to deficit irrigation for 8 weeks (watering to 50% of field capacity), transgenic plants showed a 13% increase in fresh weight than the wild type under the same drought condition. These results suggest that the AtLOS5 transgenic cotton plants acquired a better drought tolerance through enhanced ABA production and ABA-induced physiological regulations.
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PMID:Overexpression of the AtLOS5 gene increased abscisic acid level and drought tolerance in transgenic cotton. 2241 84


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