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:3.1.27.4 (ribonuclease)
6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of zinc supplementation on levels of various blood constituents and the outcome of pregnancy in 213 Hispanic women attending a prenatal clinic in Los Angeles was assessed in this double-blind study. The women were randomized into either a control (C) or a zinc-supplemented (Z) group and received similar vitamin and mineral supplements except that 20 mg zinc was added to the Z group's capsules. At the final interview, women (C + Z) with low serum Zn levels (less than or equal to 53 micrograms/dl) had higher (p less than 0.01) mean ribonuclease activity and lower (p less than 0.01) mean delta-aminolevulinic acid dehydratase activity than women with acceptable serum zinc levels. The incidence of pregnancy-induced hypertension was higher (p less than 0.003) in the C than in the Z group, but pregnancy-induced hypertension was not associated with low serum zinc levels at either the initial or final interview. The expected increase in serum copper levels was greater (less than 0.001) in women with pregnancy-induced hypertension (C + Z) than in normotensives. Except for pregnancy-induced hypertension, there was a higher incidence of abnormal outcomes of pregnancy in the noncompliers than in the compliers (C + Z).
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PMID:Zinc supplementation during pregnancy: effects on selected blood constituents and on progress and outcome of pregnancy in low-income women of Mexican descent. 647 22

Administration of zinc (Zn) simultaneously with lead (Pb) into the chick egg yolk sac reduced the accumulation of Pb and Pb-induced alterations in the activities of acid phosphatase, beta-glucuronidase and ribonuclease in the brain of the embryo. The results suggest protection against toxic effects of Pb by Zn.
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PMID:Effect of zinc on lead-induced changes in brain lysosomal enzymes in the chick embryo. 669 89

Viroids are small "naked" infectious RNA molecules that are pathogens of higher plants. The potato spindle tuber viroid (PSTV) is composed of a covalently closed circular RNA molecule containing 359 ribonucleotides. The properties of PSTV were compared with those of the scrapie agent, which causes a degenerative neurological disease in animals. PSTV was inactivated by ribonuclease digestion, psoralen photoadduct formation, Zn2+ -catalyzed hydrolysis, and chemical modification with NH2OH. The scrapie agent resisted inactivation by these procedures, which modify nucleic acids. The scrapie agent was inactivated by proteinase K and trypsin digestion, chemical modification with diethylpyrocarbonate, and by exposure to phenol, NaDodSO4, KSCN, or urea. PSTV resisted inactivation by these procedures, which modify proteins. Earlier evidence suggested that the scrapie agent is smaller than PSTV. Its small size seems to preclude the presence of a genome coding for the protein(s) of a putative capsid. The properties of the scrapie agent distinguish it from both viroids and viruses and have prompted the introduction of the term "prion" to denote a small proteinaceous infectious particle that resists inactivation by procedures that modify nucleic acids.
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PMID:Viroids and prions. 681 55

Male Sprague-Dawley rats (125 g) were fed by gastric tube either a zinc-deficient or a zinc-adequate diet for 32 days. In an additional study, rats were administered similar diets per os. Growth rate, zinc levels in plasma and tissues, and selected enzyme activities were measured. In tube fed rats receiving 13.5 g/day of a zinc-deficient diet, growth rates were similar to controls for 25 days but were somewhat lower by 32 days. The mean food intake of the rats fed the zinc-deficient diet per os was 7.6 +/- 2.1 g/day, and on day 25 growth rate was significantly lower than pair-fed and ad libitum-fed controls. Zinc levels of plasma and tissues and delta-aminolaevulinic acid dehydratase (ALAD) activity in erythrocytes and liver were reduced in rats fed the zinc-deficient diet in both studies. Alkaline ribonuclease activity remained unchanged. The larger nutrient intake provided by gastric tube feeding appears to delay the growth-retarding effect of zinc-deficient diets, but changes in zinc tissue levels and ALAD activity are similar in tube fed and per os fed rats.
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PMID:Growth rate, tissue zinc levels and activities of selected enzymes in rats fed a zinc-deficient diet by gastric tube. 682 14

Oncofetal markers for colon carcinomas are CSAp, a nonsulfated mucin, a second trimester fetal antigen, an altered thymidine kinase, a monosialoganglioside, and glycolipid antigens. For gastric carcinoma, they are basic fetoprotein, a sulfoglycoprotein, and for pancreatic carcinomas--POA, an oncofetal pancreatic antigen, and designated as CAPI, an oncofetal antigen. Tumor-associated markers for colon carcinomas are: UDP-galactosyltransferase and zinc glycinate marker; for gastric carcinomas, sulfated glycoprotein and for pancreatic carcinomas, pancreas carcinoma-associated antigen, a polycytidylic acid-specific ribonuclease, and galactosyltransferase. Suggested as tumor-specific markers for colon carcinomas are an altered mucoprotein, basic antigen, beta 2-microglobulin-associated antigen, and a specific adenosine deaminase; for gastric carcinomas, a specific protein, an antigen with 3-oxyanthranilic acid, and an antigen of unknown origin in gastric secretions; for pancreatic carcinomas, an antigen with molecular weight of 380,000 daltons and an antigen suggested by tumor immunity.
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PMID:Gastrointestinal tumor markers, other than carcinoembryonic antigen, and alpha fetal protein. 688 74

Subnormal plasma zinc levels and decreased zinc concentration in hair and leucocytes as well as increased plasma ammonia and ribonuclease activity in dialyzed and nondialyzed uremic patients indicate that zinc metabolism is abnormal in uremia and is not corrected by dialysis. The effect of oral supplementation with zinc acetate (12 patients) or placebo (12 patients) on the above biochemical parameters in hemodialysis patients was determined as a part of a double-blind study. The zinc-supplemented, but not the placebo, group demonstrated significant increases in mean (+/- SD), plasma zinc (80 +/- 9 to 110 +/- 14, micrograms/dl), leucocyte zinc (56 +/- 13 to 1098 +/- 18, micrograms/10(10) cells), hair zinc (140 +/- 12 to 190 +/- 16 micrograms/g), and decreases in plasma ammonia (76 +/- 10 to 40 +/- 6 micrograms/dl) and plasma ribonuclease activity (1.49 +/- 0.08 to 0.78 +/- 0.10, OD/min/ml). Abnormalities of taste and sexual function improved significantly in patients receiving zinc but not in those on placebo therapy. These improvements in biochemical as well as clinical parameters confirm and extend our earlier observations of improvement in taste and sexual function after zinc supplementation. Together, they suggest that zinc deficiency is a complicating feature of uremia and can be corrected by oral zinc supplementation.
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PMID:Zinc deficiency: a reversible complication of uremia. 689 Jul 61

The acid deoxyribonuclease was isolated from Bombyx mori eggs and its physico-chemical properties were investigated. The enzyme purified 160-fold did not contain admixtures of phosphomono- and phosphodiesterases or ribonuclease. The molecular weight of the enzyme is 40 000 +/- 1000, isoelectric point lies at 6.5. The maximum activity is revealed at pH 5.2, 50 degrees. The DNAase is insignificantly activated by Mg2+ and is inhibited by Cu2+ and Zn2+. The enzyme preferentially hydrolyzes native DNA and is an endonuclease splitting DNA down to 5'-oligonucleotides.
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PMID:[Isolation, purification and properties of acid deoxyribonuclease from silkworm Bombyx mori eggs]. 707 75

The addition of microelements (Co2+, Cu2+, Zn2+, and Fe2+) to a cultivation medium increased the activity of phosphomonoesterase but not of proteinase and ribonuclease. Glucose and inorganic phosphate (Pi) were the main factors that affected the direction and intensity of the biosynthesis of extracellular enzymes.
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PMID:[Regulation of biosynthesis of intracellular enzymes in Bacillus intermedius 3S-19]. 747 35

This study investigates the effects of hypoxia and of cobalt on erythropoietin (EPO) gene expression in hepatocytes in vivo and in vitro in neonatal, juvenile, and adult rats. With the use of the ribonuclease protection assay to quantify RNA, both hypoxia (0.1% CO or 9% O2) and cobalt (60 mg/kg) elicit production of increased amounts of EPO mRNA in neonatal and juvenile rat liver in vivo. In vitro hepatocyte EPO gene expression could be reproducibly stimulated by hypoxia (3% O2) but not by cobaltous chloride (50-150 microM) within 2-20 h. Conversely, cobalt substantially attenuated the rise of EPO mRNA levels in response to hypoxia. This inhibitory effect of cobalt was mimicked by zinc but not by other metals. CO attenuated the rise of EPO mRNA levels in vitro in response to hypoxia; this inhibitory effect coincided with an inhibition of total RNA synthesis as determined by [3H]uridine incorporation. The lack of specific inhibitory effects of CO and of specific stimulatory effects of cobalt on hepatocyte EPO gene expression in vitro suggests that a specific heme oxygen sensor may be less important than in hepatoma cells.
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PMID:Cobalt exerts opposite effects on erythropoietin gene expression in rat hepatocytes in vivo and in vitro. 750 28

To study the interaction and the role of the metal ion in the reaction catalyzed by Escherichia coli ribonuclease HI (E. coli RNase HI), substrate analogues containing a phosphorothioate linkage or 2'-modified nucleosides at the cleavage site were used. In the presence of Mg2+, Mn2+, Co2+, Zn2+, or Cd2+, the phosphorothioate linkage with the RP-configuration was cleaved, while the SP-isomer was not. Kinetic studies showed that Mn2+ and Cd2+ facilitated the cleavage of the phosphorothioate to only a small extent, which indicated the absence of an interaction between the metal ion and this phosphate residue. The interaction of the metal ion with the 2'-functional group was analyzed by Mg(2+)-titration experiments using the -OH, -NH2, and -F substrates. From Hill plots, it was found that the KMg values were almost the same. These results are evidence of an interaction between Mg2+ and the 2'-functional group by the formation of an outer-sphere complex with a water molecule. The Hill coefficient of 1.0 for the -OH substrate indicated that a single Mg2+ ion is required for the catalysis.
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PMID:Role of the Mg2+ ion in the Escherichia coli ribonuclease HI reaction. 770 24


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