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)

An extract made from the supernatant of Neisseria gonorrhoeae Gc2 strain 1291 degraded the Gc2 polysaccharide antigen. Chemical analysis of this polysaccharide indicated it contains glucose, galactose, glucosamine, galactosamine, glucosamine-6-phosphate, heptose, 2-keto-3-deoxyotonate, and ethanolamine and is the polysaccharide component of gonococcal lipopolysaccharide. Degradation of the polysaccharide by sonic extracts resulted either in complete loss of antigenicity and immunogenicity or in partial degradation to subunits that could inhibit the Gc2-specific hemagglutination inhibition. The factors responsible for degradation were destroyed by heating at 100 degrees C for 5 min or by Pronase digestion, but were unaffected by ribonuclease, deoxyribonuclease, Mg2+, Ca2+, or ethylenediaminetetraacetic acid. The process was pH dependent, with optimal activity occurring at pH 7. Sonic extract supernatants from group B and C meningococcal strains contained degrading properties, whereas similar extracts produced from Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Streptococcus pneumoniae type II failed to degrade the Gc2 polysaccharide.
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PMID:Degradation of the polysaccharide component of gonococcal lipopolysaccharide by gonococcal and meningococcal sonic extracts. 7 94

Dipolid human fibroblast-rich tissues contain a macromolecule with a molecular weight between 30,000 and 50,000 daltons which will inhibit the proliferation of fibroblasts in the G1 phase of the cell cycle (i.e., inhibit both 3H-thymidine uptake as well as the normal increase in cell number). The inhibitor is destroyed by trypsin but not by ribonuclease or deoxyribonuclease, and it is thermolabile. It has an acid IEP. It is not cytotoxic, and its inhibitory activity appears to be completely reversible. This fibroblast endogenous inhibitor does not interfere with the proliferation of DNA synthesis by human lymphocytes, bronchial carcinoma cells, or HeLa cells. The activity does not appear to be species specific. Therefore, we suggest that it is quite possible that the control of fibroblast proliferation resides in a fibroblast chalone. Diploid human fibroblasts, in contrast to chicken or mouse fibroblasts or heteroploid fibroblasts in general, stringently require serum for their proliferation. All of this mitogenic activity of calf serum can be concentrated in a molecular weight range around 100,000 daltons by ultrafiltration. All of the mitogenic activity within this molecular weight class can be concentrated at a pH of 5.2 via isoelectric focusing, and all of the activity at this isoelectric point can be concentrated in one peak on preparative polyacrylamide gel electrophoresis. This latter material is homogeneous at three different pH's in analytical gel electrophoresis as well as in SDS electrophoresis. This purified serum mitogen for diploid human fibroblasts in vitro also works in vivo and represents as much as 0.5% of calf serum protein, albeit there is much less of this protein in adult cow or horse. It is composed of two equal subunits weighing about 60,000 daltons each and contains about 2 moles of sialic acid, one S-S bond, and 6 moles of hexose per subunit. There is a reciprocal relationship between the biological activity of fibroblast inhibitor and serum mitogen, but there is no apparent direct interaction between these two proteins. Addition of pure serum mitogen to diploid human fibroblasts in vitro results in the release of commensurable chalone activity into the medium and a reciprocal loss of mitogen from the medium. Therefore, we propose that serum contains a single macromolecule which competes with endogenous chalone on the surface of diploid human fibroblasts and that this functions as an anti-chalone for the fibroblast.
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PMID:Circulating factors controlling cell proliferation. 13 64

Several closely related capsular polysaccharides were isolated from a strain of Clostridium perfringens Hobbs 9 type A by extraction of encapsulated cells with cold 0.85% NaCl. The soluble polymers were precipitated with alcohol and purified by (NH4)2SO4 fractionation, enzymatic digestion with papain and ribonuclease, and chromatography on diethylaminoethyl-Sephadex A25. The polysaccharides were composed mainly of glucose, galactose, and galactosamine. The major fraction contained these constituents (representing 77% of the dry weight) in a molar ratio of 1:1.6:1.1. All of the fractions contained phosphate and peptide material that was not removed during purification. The polysaccharides were closely related but not identical as indicated by double-diffusion-in-gel experiments. Immunoelectrophoresis in agarose demonstrated that the polysaccharides had identical mobilities and that no resolution into additional fractions occurred. The immunological activity of all the purified polysaccharides was destroyed by periodate oxidation but was unaffected by protease.
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PMID:Capsular polysaccharide of Clostridium perfringens Hobbs 9. 19 74

Membrane-defective mutants of Escherichia coli J5 were isolated on the basis of supersensitivity to the antibiotic novobiocin. These mutants display an increased sensitivity to a wide range of antibiotics and to several dyes and detergents. In addition, several mutants leak the periplasmic enzymes, alkyline phosphatase and ribonuclease. This evidence indicates an outer membrane defect in these mutants. The inner and outer membranes of one mutant were separated and subjected to compositional analysis. A deficiency in galactose containing lipopolysaccharide in the outer membrane of the mutant was observed. Two possible causes of this deficiency were examined and discounted: defective galactose uptake into the cell, and defective translocation of lipopolysaccharide from the inner membrane. Extraction and chemical analysis of mutant and wild type lipopolysaccharides suggests that the mutant is defective in the enzyme which transfers glucose to the growing lipopolysaccharide core, UDPglucose transferase. Thus, the mutant's deficiency in galactose-containing lipopolysaccharide can be ascribed to the fact that addition of glucose to the lipopolysaccharide core is a prerequisite for galactose addition. The physiological implications of this alteration are discussed.
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PMID:Biosynthesis and structure of lipopolysaccharide in an outer membrane-defective mutant of Escherichia coli J5. 32 11

From a strain of Escherichia coli with two copies of the tryptophan (trp) operon and one copy of the lactose (lac) operon, under control of one of the trp regulatory elements, we have isolated a mutant which does not grow in a medium containing 19 amino acids, unless tryptophan is added, and which cannot ferment lactose. The apparent pleiotropic nature of the mutation(s) is indicated by the very slow growth of mutant bacteria on minimal-medium agar supplemented with glucose and tryptophan. The amount of the trp enzymes (anthranilate synthetase and tryptophan synthetase) and trp messenger ribonucleic acid is reduced several-fold in the mutant compared to the isogenic wild-type strain, whereas the enzymes tryptophanyl-transfer ribonucleic acid synthetase and glucose 6-phosphate dehydrogenase remain the same. The incorporation of radioactive label into pulse-labeled but not into stable ribonucleic acid is significantly lower. Our results suggest that in the mutant organism the control of transcription of some operons, including the trp operon, is modified. An alternative explanation is that mutant bacteria contain a ribonuclease with increased activity for some messenger ribonucleic acid species.
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PMID:Escherichia coli mutant strain with altered expression of the tryptophan operon: isolation and preliminary characterization. 37 67

Thirty-nine strains of gram-positive microaerophilic cocci isolated from cases of heifer and dry-cow mastitis were biochemically characterized with the API 50E and API-ZYM test kit systems, gas-liquid chromatography for analysis of end products of glucose metabolism, and anaerobic biochemical tests (L. V. Holdeman, E. P. Cato, and W. E. C. Moore, Anaerobe Laboratory Manual, Virginia Polytechnic Institute, Blacksburg, 1977). Strains were screened for production of a variety of extracellular enzymes on substrate-containing agar plates and for hemolysin and coagulase production. Antibiotic susceptibility and sensitivity tests were also performed. The microaerophilic cocci displayed homogeneity with respect to the majority of the biochemical tests used; i.e., greater than or equal to 90% of the strains were consistently positive or negative in any one test and probably represent one species. All produced deoxyribonuclease, ribonuclease, and hyaluronidase, and 92% were positive for chondroitin sulfatase. Catalase and coagulase tests were negative. Greening was observed on bovine blood agar. Acetic and succinic acids were produced by all strains as the only detectable products of glucose metabolism. The strains were susceptible to penicillin G, cefoxitin, doxycycline, and chloramphenicol and were resistant to clindamycin, novobiocin, and metronidazole. Their taxonomic position remains unclear.
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PMID:Biochemical characterization of unidentified microaerophilic cocci isolated from heifer and dry-cow mastitis. 39 19

Lipopolysaccharides, extracted by phenol-water from five strains fo Neisseria gonorrhoeae, were purified by treatment with ribonuclease followed by multiple washes. These preparations were fatal to mice when administered in submicrogram amounts with actinomycin D, the LD50 values varying from 4 to 16 mug/kg. Analyses showed that all preparations contained glucose, galactose, glucosamine, heptose, 2-keto-3-deoxyoctonic acid and phosphate. All the lipopolysaccharides contained the same fatty acids, namely beta-OH-10:0, beta-OH-12:0, beta-OH-14:0, 12:0, 14:0,16:0, 16:1, 18:0 and 18:1. We were unable to detect significant differences between the lipopolysaccharides of virulent and avirulent gonococci or between penicillin-sensitive and resistant strains. Gonococcal lipopolysaccharides appeared to lack O-antigen side chains.
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PMID:Studies on lipopolysaccharides isolated from strains of Neisseria gonorrhoeae. 80 76

The addition of trypsin [EC 3.4.21.4]-digested liver microsimes induced cyanideinsensitive respiration in guinea pig polymorphonuclear leucocytes with concomitant acceleration of the hexose monophosphate oxidative pathway. The respiration was insensitive to inhibitors of mitochondrial respiration but sensitive to glycolytic inhibitors. These metabolic alterations are similar to those associated with phagocytosis, though the digested mocrosomes were apparently not taken up by the cells and prpbably trigger the netabolic changes by interaction with the cellular membrane. Intact microsomes or microsomes treated with chymotrypsin [EC 3.4.21.1], bacterial proteinase, ribonuclease [EC 3.1.4.22], or neuraminidase [EC 3.2.1.18] could not induce such respiration.
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PMID:Metabolic pattern of polymorphonuclear leucocytes induced by trypsin-digested microsomes. 115 Jun 33

Reducing sugars react with protein amino groups to form a diverse group of protein-bound moieties with fluorescent and cross-linking properties. These compounds, called advanced glycosylation end products (AGEs), have been implicated in the structural and functional alterations of proteins that occur during aging and long-term diabetes. Although several AGEs have been identified on the basis of de novo synthesis and tissue isolation procedures, the measurement of AGE compounds in vivo has remained difficult. As an approach to the study of AGE formation in vivo, we prepared polyclonal antiserum to an AGE epitope(s) which forms in vitro after incubation of glucose with ribonuclease (RNase). This antiserum proved suitable for the detection of AGEs which form in vivo. Both diabetic tissue and serum known to contain elevated levels of AGEs readily competed for antibody binding. Cross-reactivity studies revealed the presence of a common AGE epitope(s) which forms after the incubation of diverse proteins with glucose. Cross-reactive epitopes also formed with glucose 6-phosphate or fructose. These data suggest that tissue AGEs which form in vivo appear to contain a common immunological epitope which cross-reacts with AGEs prepared in vitro, supporting the concept that immunologically similar AGE structures form from the incubation of sugars with different proteins (Horiuchi, S., Araki, N., and Morino, Y. (1991) J. Biol. Chem. 266, 7329-7332). None of the known AGEs, such as 4-furanyl-2-furoyl-1H-imidazole, 1-alkyl-2-formyl-3,4-diglycosylpyrrole, pyrraline, carboxymethyllysine, or pentosidine, were found to compete for binding to anti-AGE antibody. These data further suggest that the dominant AGE epitope which forms from the reaction of glucose with proteins under native conditions is immunologically distinct from the structurally defined AGEs described to date.
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PMID:Immunochemical detection of advanced glycosylation end products in vivo. 137 95

It was found, in cell-free assays, that the Man8GlcNAc2 and Man7GlcNAc2 isomers having the mannose unit to which the glucose is added were glucosylated by the rat liver glucosyltransferase at 50 and 15%, respectively, of the rate of Man9GlcNAc2 glucosylation. This indicates that processing by endoplasmic reticulum mannosidases decreases the extent of glycoprotein glucosylation. All five different glycoproteins tested (bovine and porcine thyroglobulins, phytohemagglutinin, soybean agglutinin, and bovine pancreas ribonuclease B) were found to be poorly glucosylated or not glucosylated unless they were subjected to treatments that modified their native conformations. The effect of denaturation was not to expose the oligosaccharides but to make protein determinants, required for enzymatic activity, accessible to the glucosyltransferase because (a) cleavage of denatured glycoproteins by unspecific (Pronase) or specific (trypsin) proteases abolished their glucose acceptor capacities almost completely except when the tryptic peptides were held together by disulfide bonds and (b) high mannose oligosaccharides in native glycoproteins, although poorly glucosylated or not glucosylated, were accessible to macromolecular probes as concanavalin A-Sepharose, endo-beta-N-acetylglucosaminidase H, and jack bean alpha-mannosidase. In addition, denatured, endo-beta-N-acetylglucosaminidase H deglycosylated glycoproteins were found to be potent inhibitors of the glucosylation of denatured glycoproteins. It is suggested that in vivo only unfolded, partially folded, and malfolded glycoproteins are glucosylated and that glucosylation stops upon adoption of the correct conformation, a process that hides the protein determinants (possibly hydrophobic amino acids) from the glucosyltransferase.
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PMID:Recognition of the oligosaccharide and protein moieties of glycoproteins by the UDP-Glc:glycoprotein glucosyltransferase. 153 Oct 24


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