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:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Electron microscope examination of the adrenal cortex from three male human subjects revealed a special type of cell occurring in periendothelial spaces, in all adrenal cortex zones. It is a clear, spindle-shaped cell the principal cytoplasmic features of which are crystalline inclusions with a structure similar to that of the Reinke crystals of human testicular interstitial cells and an abundance of microfilaments. Enzymatic digestions with pronase, pepsin, and ribonuclease were performed, and no digestion of the crystals was obtained. The crystals had no peroxidase or acid phosphatase activities. This cell appears to be exclusive to human males and it may be related to adrenal androgen secretion.
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PMID:A new crystal-containing cell in human adrenal cortex. 434 48

Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3-10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase, beta-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.
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PMID:Purification and partial characterization of four proteins from human parotid saliva. 500 93

The availability of very high magnetic fields of up to 170,000 gauss made it worthwhile to pursue the search for a critical change in the rate of four enzyme substrate reactions. The four enzymes were ribonuclease, polyphenol oxidase, peroxidase, and aldolase. The experiments showed that, to within +/-3%, no detectable change was observable in the rate of reaction of any of the systems for periods of exposure to the magnetic field of up to 20 min.
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PMID:Enzyme-substrate reactions in very high magnetic fields. I. 604 70

Cross-linked dimers of ribonuclease, added at a concentration of 0.05 mg/ml to the culture medium of hepatoma (HTC) cells, were previously shown to inhibit intracellular degradation of peroxidase taken up by endocytosis. Intracellular localization showed that endocytosed peroxidase does not reach lysosomes in dimer-treated cells. The present study shows that preloading of lysosomes with fluorescent anti-peroxidase IgG, obtained by exposing HTC cells for 48 h to 0.1 mg of antibody/ml, restores intracellular degradation of endocytosed peroxidase. Moreover, accumulation of peroxidase into lysosomes, which no longer occurs in dimer-treated cells, occurs again under these conditions. We conclude that inhibition of transfer of peroxidase from phagosomes to lysosomes is most likely to be the alteration resulting from the exposure of the cells to ribonuclease dimer, rather than inhibition of fusion between phagosomes and lysosomes. The dimer of another basic protein, lysozyme added at a concentration of 0.2 mg/ml to the culture medium, is shown to induce the same type of effects as does the dimer of ribonuclease; the half-life of endocytosed peroxidase increased from 5 to 15 h after 2 h exposure of HTC cells to dimerized lysozyme. The effect of both dimers on intracellular protein processing can be reversed by addition of 100 mm-galactose to the culture medium, up to 5 h after pretreatment of the cells. The dimers of ribonuclease A or of lysozyme have thus probably the same mechanism of action. Evidence that the two dimers share the same binding sites on the cells is presented.
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PMID:Effects of cross-linked dimers of ribonuclease A or of lysozyme on the processing of endocytosed peroxidase by hepatoma cells. 628 32

Insulin, ribonuclease, papain and collagen solutions saturated with nitrogen, N2O or air were irradiated with doses of 10 to 640 Gy of gamma rays. Protein solutions were also oxidized enzymatically in a system of horse-radish peroxidase: hydrogen peroxide. Column chromatography (Sephadex G-75 or Sephacryl S-200) of treated protein solutions revealed that they contain protein molecular aggregates. Nitrogen saturation of solution before irradiation was most favourable for radiation-induced aggregation of proteins. Fluorescence analysis of protein solutions resulted in detection of dityrosyl structures in irradiated as well as in enzymatically oxidized proteins. Concentration of dityrosine in proteins studied was determined fluorimetrically in their hydrolysates separated on BioGel P-2 column. In irradiated proteins, dityrosine was present almost exclusively in their aggregated forms. In proteins oxidized enzymatically, dityrosine was also present in fractions containing apparently unchanged protein. Mechanisms which could account for differences in the yield of dityrosine formation in radiolysis and in enzymatic oxidation of proteins are suggested.
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PMID:Radiolytic and enzymatic dimerization of tyrosyl residues in insulin, ribonuclease, papain and collagen. 633 34

Acid-acting (pH 6-7) (presumably lysosomal) ribonuclease and neutral-acting (pH 7-8) calcium-dependent phospholipase A2 (presumably the enzyme releasing arachidonic acid from membrane phospholipids) were demonstrated by the peroxidase-antiperoxidase (PAP) immunocytochemical technique in rabbit professional phagocytes: pulmonary alveolar macrophages (AM), oil-induced peritoneal exudate macrophages (M phi) and glycogen-induced peritoneal exudate polymorphonuclear granulocytes (PMN). All three cell types stained positively with antisera to purified rabbit lung RNase and purified rabbit granulocyte phospholipase A2. The RNase and phospholipase A2 were also demonstrated by the PAP technique in the activated macrophages and granulocytes present in tissue sections of tuberculous (BCG) lesions. The intensity of staining of these two enzymes in individual macrophages did not change appreciably as the BCG lesions developed and regressed, but there were more macrophages rich in both enzymes when the lesions reached their peak size at 21 days. When the anti-RNase serum was fractionated by immunoabsorbent chromatography, the anti-delta RNase serum fraction stained exudate M phi and PMN better than AM; and the anti-beta RNase fraction stained AM better than M phi and PMN. Similar to isolated phagocytes, tissue granulocytes stained best with the anti-delta fraction; and activated tissue macrophages stained best with the anti-beta fraction. Thus, macrophages and granulocytes contain two types of RNase, beta and delta; and the beta RNase is associated with macrophage activation.
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PMID:Immunocytochemical demonstration of rabbit ribonuclease and phospholipase A2 by the peroxidase-antiperoxidase technique in professional phagocytes (pulmonary alveolar macrophages and granulocytic and mononuclear peritoneal exudate cells) and in glycol methacrylate sections of dermal tuberculous (BCG) lesions. 636 Dec 53

A pancreas-specific antigen was identified by immunologic techniques and purified from saline extract of human pancreas. The purified pancreas-specific antigen was shown to be homogeneous by polyacrylamide gel electrophoresis under both denaturing and non-denaturing conditions. It had a molecular weight of 44000 as estimated by gel filtration or sodium dodecyl sulfate-gel electrophoresis, and a sedimentation coefficient of 3.4 S as analyzed by sucrose gradient centrifugation. Pancreas-specific antigen possessed an isoelectric point of 4.9 and migrated to alpha-beta region upon immunoelectrophoresis. By colorimetric assay procedures, pancreas-specific antigen exhibited no enzyme activity, such as amylase, protease, esterase, lipase, acid phosphatase, alkaline phosphatase peroxidase, deoxyribonuclease or ribonuclease. Immunoreactivity of pancreas-specific antigen was sensitive to proteolytic enzymes, perchloric acid and high temperature (70 degrees C, 10 min); but insensitive to neuraminidase or beta-glucosidase. Immunohistochemical staining revealed that pancreas-specific antigen was located in acinar cells of human pancreas. In addition, a higher concentration of pancreas-specific antigen was detected in pancreatic juice than in the saline extract of pancreas. This newly identified pancreas-specific antigen, therefore, may be a useful marker protein in physiological studies of pancreas and pancreatic secretion.
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PMID:Purification and characterization of a human pancreas-specific antigen. 678 69

Low dosages of chloramphenicol (25-50 micrograms/ml) brought about a 2-4-fold stimulation of acid phosphatase activity in 48 h-germinated cotton (Gossypium hirsutum) embryos. However, at high concentrations of chloramphenicol (100-1000 micrograms/ml), there was a progressive decline in enzyme activity. The stimulatory effect of the drug on acid phosphatase activity was relatively specific, since no significant stimulation of activities of proteinase, deoxyribonuclease, ribonuclease, o-diphenolase and peroxidase was observed in germinating cotton embryos. Chloramphenicol, however, did promote the activities of isocitric lyase and alkaline phosphatase. Sephadex G-200 chromatography of the enzyme fraction revealed high (230 000)- and low (106 000)-molecular-weight multiple forms of acid phosphatase in the chloramphenicol-treated embryos, in contrast with a single molecular form (mol.wt. 106 000) in the untreated embryos. Thus the treatment of cotton embryos with chloramphenicol induced both a qualitative and a quantitative change in the acid phosphatase activity. Chloramphenicol-stimulated acid phosphatase activity was strongly inhibited when Pi was included in the germination medium. However, the control embryos showed less pronounced inhibition of enzyme activity in presence of Pi ions.
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PMID:Chloramphenicol stimulates acid phosphatase activity in germinating cotton (Gossypium hirsutum) embryos. 687 Aug 57

Treatment of spectrin, insulin, glucagon and ribonuclease with ozone results in covalent cross-linking of these proteins. This cross-linking is not reversed by treatment with dithiothreitol and thus can not be ascribed to -S-S- bond formation. A concomitant O,O'-dityrosine formation is observed by spectrofluorometric analysis of the protein and by amino acid analysis and thin-layer chromatography of hydrolyzed protein samples. It is highly probable that the observed protein cross-linking should be attributed to interpeptide O,O'-dityrosine bonds. Several authors have shown before that oxidation of proteins with horseradish peroxidase and H2O2 also leads to O,O'-dityrosine formation. Peroxidase-induced O,O'-dityrosine formation in galactose oxidase (d-galactose:oxygen 6-oxidoreductase, EC 1.1.3.9) causes a strong increase of enzyme activity. In accordance with these observations ozone treatment of galactose oxidase also leads to O,O'-dityrosine formation with a concomitant 8-fold increase of enzyme activity.
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PMID:Ozone-induced formation of O,O'-dityrosine cross-linked in proteins. 704 79


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