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)

Snapping turtle (Chelydra serpentina) ribonuclease was isolated from pancreatic tissue. Turtle ribonuclease binds much more weakly to the affinity chromatography matrix used than mammalian ribonucleases. The amino acid sequence was determined from overlapping peptides obtained from three different digests. The N-terminal amino acid sequence of the protein determined by others [E. A. Barnard, M. S. Cohen, M. H. Gold J.-K. Kim (1972) Nature (Lond.) 240, 395-398] and homology were used as additional evidence for several overlaps. The polypeptide chain consists of 119 amino acid residues. Compared to most ribonucleases the N-terminal residue, three residues in the loop near residue 71 and two residues in the loop near residue 114 are deleted, and there is one additional residue in the loop near residue 23. The half-cystines at positions 65 and 72, which form a disulfide bond in mammalian ribonucleases, are not present in turtle ribonuclease. Turtle ribonuclease differs from bovine ribonuclease at 70 of the 118 positions where both proteins have amino acid residues. Turtle ribonuclease contains no carbohydrate, although the enzyme possesses a recognition site for carbohydrate attachment in the sequence Asn-Ala-Ser (positions 76-78).
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PMID:The amino acid sequence of snapping turtle (Chelydra serpentina) ribonuclease. 407 78

Histochemical techniques were used to study the nature of acidophilic hyaline clubs arranged radially at the peripheries of Actinomyces colonies in infected lung tissues of two persons. Concentrations of arginine-rich polypeptides were demonstrated in the acidophilic areas and in the cytoplasm of granulocytic leukocytes surrounding the colonies. Exposure of Actinomyces organisms to strongly cationic polypeptides (protamine, histone) in vitro killed the organisms and caused them to develop acidophilic staining. Weakly cationic proteins, ribonuclease, and hemoglobin produced no such effects. No acidophilic component could be detected in fresh broth-grown organisms themselves. Viable and nonviable colonies of the test strain lacking hyaline clubs were injected beneath the skin of guinea pigs. Agrinine-rich cationic polypeptides were evident in the cytoplasm of surrounding leukocytes and permeating the microbial colonies. In light of current evidence pertaining to leukocyte lysosomes and capsule production by Actinomyces and related organisms, the acidophilic hyaline clubs observed in human tissues appear to be a combination of a capsular component of the actinomycete and a cationic polypeptide component of host leukocytes. Organisms deeper in the human tissue colonies retained their normal basophilic reaction, suggesting a protective role for the peripheral hyaline club matrix. The acidophilic club complexes serve to indicate the reaction of cationic polypeptides in response of the human host to infecting Actinomyces organisms. These observations also support a broader concept that antimicrobial polypeptides of leukocyte lysosomes are an important factor in response of both the human and animal host to infecting bacteria.
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PMID:Interaction of Actinomyces organisms with cationic polypeptides. I. Histochemical studies of infected human and animal tissues. 411 93

After the attachment of radioactive coxsackievirus B3 to HeLa cells at 0 C and subsequent incubation at 37 C, 50 to 80% of attached virus radioactivity was eluted from the cells within 1 hr. Eluted virus had a buoyant density of 1.21 in a potassium tartrate gradient, sedimented more slowly than native virus in sucrose gradients, was resistant to ribonuclease, was unstable in CsCl centrifugation, and did not reattach to uninfected cells. Electrophoretic studies of sodium dodecyl sulfate-disrupted B3 virus in sodium dodecyl sulfate-polyacrylamide gels revealed four radioactive virus polypeptides (VP 1 to 4), of which the three largest migrated slightly faster than their poliovirus T1 counterparts. In contrast, electrophoretic analysis of eluted virus, after banding in a tartrate gradient or pelleting by centrifugation, showed the absence of the fastest migrating polypeptide, VP 4. VP 4 was recovered in the supernatant fluid when the eluted virions were removed by high-speed centrifugation. The results indicate that VP 4 is located at the surface of the native virion, and its dissociation from the capsid may represent the first specific alteration of the virion after virus-receptor interaction at the cell surface.
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PMID:Specific alterations of coxsackievirus B3 eluted from HeLa cells. 433 54

Undegraded polyribosome preparations may be obtained from chick intestinal mucosa if ribonuclease activity is strictly controlled. This is best achieved by homogenization of the mucosa directly in rat liver cell-sap. 2. The extent of amino acid incorporation by chick intestinal polyribosomes is greatly influenced by the source of the cell-sap. Sephadex-treated intestinal cell-sap caused impaired incorporation and release of completed polypeptide chains, whereas Sephadex-treated rat liver cell-sap promoted the polymerization of up to 90 amino acids per ribosome. Under optimum conditions 30-35% of the nascent polypeptide chains are completed and released. 3. The preparation of an antiserum against the calcium-binding protein formed in response to vitamin D is described. It is shown that the antiserum is highly specific for calcium-binding protein. 4. This antiserum was used to investigate the ability of chick intestinal polyribosomes to synthesize calciumbinding protein. Only polyribosomes from chicks receiving vitamin D have the ability to synthesize calcium-binding protein. Moreover, the product formed in vitro has the same electrophoretic mobility as calcium-binding protein synthesized in vivo. 5. It is concluded that one of the main functions of vitamin D in the small intestine is to induce the synthesis de novo of calcium-binding protein.
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PMID:The response of the small intestine to vitamin D. Isolation and properties of chick intestinal polyribosomes. 445 90

In order to resolve the functional role of intact rRNA in polypeptide chain elongation mouse brain ribosomes were treated with dilute pancreatic or T(1) RNAase (ribonuclease). After RNAase treatment, several physical-chemical properties as well as the functional activity of the ribosomes were measured. RNAase treatment resulted in the extensive hydrolysis of both 18S and 28S rRNA; however, the sedimentation properties of mono-ribosomes were unaltered and more than 90% of the relatively low-molecular-weight RNA fragments remained associated with ribosome particles. Analysis of the ability of RNAase-treated ribosomes to participate in cell-free protein synthesis showed that ribosomes with less than 2% intact rRNA retained more than 85% of their activity in polyphenylalanine incorporation. Proof that the incorporation of phenylalanine by ribosomes with hydrolysed rRNA actually represented active translocation was obtained by the effective inhibition of incorporation by diphtheria toxin. In addition, the oligopeptide products of protein synthesis could be identified by BD (benzoylated diethylaminoethyl)-cellulose column chromatography. Analysis of the size distribution of oligopeptides synthesized by normal and RNAase-treated ribosomes showed no significant differences which indicated that there was no change in the proportion of ribosomes engaged in protein synthesis. Thus strong RNA-protein and protein-protein interactions must serve to maintain the functional integrity of ribosomes even when the rRNA is extensively degraded. The ability of the enzyme-treated ribosomes to efficiently incorporate amino acids clearly demonstrated that ;intact' rRNA is not required for protein-synthetic activity.
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PMID:The role of ribosomal ribonucleic acid in the structure and function of mammalian brain ribosomes. 446 59

The vitamin B(12)-binding property of Lactobacillus leichmannii ATCC 7830 has been studied. The organism could bind 0.52 mug of B(12) per mg of cells. With regard to the cellular site for B(12) accumulation, three-quarters of the B(12) bound to the cell was found in the crude cell wall fraction, and the remaining one-quarter was found in the particulate (ribosome) fraction. After receiving enzymatic treatments with ribonuclease, lipase, and trypsin, the wall fraction retained three-fifths of the initial B(12). The possibility of cross-contamination of the wall and particulate fractions was excluded by measuring the contents of ribonucleic acid and hexosamines in each fraction. The B(12)-binding activity of the wall was destroyed by pretreatment of the wall with pepsin, Pronase, or trypsin. However, once bound to the wall, the B(12) was not released by the same treatments. These facts suggest that B(12) is bound to a polypeptide in the wall on which these enzymes act and that, once bound, B(12) somehow inhibits the enzymatic actions as described earlier with L. delbrueckii no. 1. A B(12)-polypeptide complex was isolated by treatment with 0.2 n HCl from walls to which B(12) had been bound. The complex was then purified. The complex moves as a single band on polyacrylamide gel electrophoresis. Its molecular weight was estimated around 21,500 with microheterogeneity on a Sephadex G-75 column. The mode of B(12) binding was found to be similar to that of L. delbrueckii.
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PMID:Further studies on the binding of vitamin B 12 to the cell wall of a B 12 -requiring Lactobacillus. 455 Jun 59

1. Cell-free protein synthesis was studied in striated and smooth muscles in an attempt to elucidate the primary genetic defect in polymyopathic hamsters. 2. When washed membrane-free polyribosomes from myopathic and control heart muscle were individually recombined with pH5 enzymes from both types of animals, the pH5 enzymes from myopathic muscle were less active in polypeptide synthesis than those from controls, irrespective of the source of polyribosomes. 3. The same defect was present in skeletal-muscle preparations. 4. Both the initial rate and the maximum extent of incorporation were affected in the defective preparations from myopathic muscle. 5. Concentration differences, with respect to total protein and RNA, were not responsible. 6. Preincubation of the pH5 enzymes resulted in a greater degree of inhibition. 7. The defect in the pH5 enzymes from myopathic muscle was also expressed in poly(U)-directed polyphenylalanine synthesis. 8. Acid proteinase activity in extracts of control and myopathic muscle was the same but general ribonuclease activity in the latter extracts was higher. 9. The defect was also present when both types of pH5 enzymes were prepared in the presence of the ribonuclease-asborbent bentonite. 10. pH5 enzymes from uterine smooth muscle, brains and livers of myopathic animals were similarly affected in homologous and heterologous combinations. 11. It is concluded that the general tissue defect is both qualitative and quantitative in nature, implying that there is a shortage of some essential soluble component in the pH5 fraction which is accompanied by the presence of an altered substituent. This prevents the attainment of extents of polypeptide synthesis in vitro obtained in control extracts from unaffected animals.
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PMID:Cell-free protein synthesis in heart and skeletal muscles from polymyopathic hamsters. 472 36

1. Different reaction steps involved in protein synthesis were studied in skeletal muscles from control and myopathic hamsters. 2. There was no difference between partially purified aminoacyl-tRNA synthetases from myopathic and control animals in yield or catalytic activity, as tested with exogenous deacylated tRNA. 3. However, isolated deacylated tRNA from myopathic muscle was aminoacylated by these synthetases to a lesser extent than that derived from control muscle. 4. Addition of deacylated tRNA isolated from control muscle improved the performance of pH5 enzymes from myopathic muscle in polypeptide synthesis on homologous polyribosomes; tRNA isolated from myopathic animals did not. 5. Preparation of extracts from both types of animals in the presence of the ribonuclease-absorbent bentonite led to an increased capacity of endogenous tRNA to accept amino acids in pH5 enzymes prepared from normal and abnormal tissue, but the difference between the two systems remained the same. 6. Total tRNA nucleotidyltransferase activity, tested with twice-pyrophosphorolysed rat liver tRNA, was identical in both extracts. 7. Added tRNA nucleotidyltransferase incorporated more AMP and CMP into endogenous tRNA with the pH5 enzyme from myopathic muscle than with that from control muscle. 8. Preincubation of deacylated tRNA from myopathic muscle with ATP, CTP and tRNA nucleotidyltransferase more than doubled its subsequent aminoacyl-acceptor activity, and halved the extent of the defect relative to aminoacylation of control tRNA similarly treated. Endogenous tRNA in pH5 enzyme preparations behaved likewise. 9. It is suggested that a 3'-exonuclease in myopathic muscles attacks tRNA molecules in such a way that some of them remain substrates for tRNA nucleotidyltransferase, which may incorporate into RNA not only AMP and CMP, but also GMP. 10. Cell-free protein synthesis in preparations from myopathic hamster muscles is limited by the supply of intact tRNA molecules.
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PMID:Evidence for defective transfer ribonucleic acid in polymyopathic hamsters and its inhibitory effect on protein synthesis. 472 37

A procedure for the isolation and purification of competence factor produced in a defined medium by group H streptococci, strain Challis-6, is presented. Partial characterization and chemical analysis of the product are described. The procedure yields competence factor of high purity, as shown by homogeneity in electrofocusing, by electrophoresis in sodium dodecyl sulfate polyacrylamide gels, and by chemical analysis. The data indicate that competence factor is a small, dialyzable, highly basic compound. It is free from lipids, phosphorus, and carbohydrates, and is colorless and thermoresistant. Its biological activity is destroyed by trypsin but not by deoxyribonuclease, ribonuclease, lipase, or lysozyme. Its high isoelectric point of above pH 11.0 suggests that competence factor may be a protamine or a polymer of basic amino acids. The possibility that a polyamine may be an integral part of the polypeptide molecule has not been excluded.
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PMID:Purification and properties of Streptococcal competence factor isolated from chemically defined medium. 501 23

The effect of reduction of intramolecular disulphide bridges on the mobility of proteins in 5% (w/v) polyacrylamide gels in the presence of sodium dodecyl sulphate was investigated. A series of polypeptide polymers, containing up to 68 intramolecular disulphide bridges, was prepared by cross-linking proteins of known structure with glutaraldehyde. These model polypeptides were denatured with heat, sodium dodecyl sulphate and urea, and their mobilities in sodium dodecyl sulphate-polyacrylamide gels compared before and after reduction with dithiothreitol. The mobilities of polypeptides containing no cystine were unaffected by reduction. However, reduction generally decreased the mobilities of polypeptides containing cystine; the extent of this decrease depended on the number of cystine residues originally present in the polypeptide polymer, and on the protein from which the latter was derived. In contrast with their higher oligomers, the monomer of lysozyme and the dimer of ribonuclease increased in mobility after reduction. The reduced polypeptide oligomers formed by reaction with glutaraldehyde were generally found to migrate at a rate significantly faster than was expected from their calculated molecular weights. It was concluded that the use of unreduced proteins and protein aggregates for molecular-weight measurements by the sodium dodecyl sulphate-polyacrylamide-gel method may give erroneous estimates of the molecular weight of any protein being investigated.
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PMID:The effect of cross-links on the mobility of proteins in dodecyl sulphate-polyacrylamide gels. 507 66


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