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)

Heat-labile enterotoxin (LT) produced by a human strain of enterotoxigenic Escherichia coli (286C(2)) was purified to homogeneity from pH extracts of fermentor-grown cells by ultrafiltration, (NH(4))(2)SO(4) fractionation, hydrophobic chromatography on norleucine-Sepharose 4B, hydroxylapatite chromatography, and Bio-Gel P-150 filtration. Purified LT preparations exhibited biological activity comparable to that of cholera toxin in four bioassays specific for the two enterotoxins (Y-1 adrenal tumor cells, Chinese hamster ovary cells, pigeon erythrocyte lysates, and skin permeability test). The overall yield of LT protein was 20%, which represented a 500-fold purification over pH extracts. A native molecular weight of 73,000 was determined by gel electrophoresis. The toxin dissociated upon treatment with sodium dodecyl sulfate, pH 7.0, into two components with molecular weights of 44,000 and 30,000. Purified LT preparations were remarkably stable over a wide range of storage conditions, temperatures, and pH's. The biological activity was increased by incubation with trypsin and completely destroyed by pronase and proteinase K, whereas deoxyribonuclease I, ribonuclease, and phospholipase D had no effect. The amino acid composition of purified LT was quite different from that of cholera toxin. Neither carbohydrate nor lipopolysaccharide was present in purified preparations. The purification scheme appeared applicable to LT produced by other human and porcine enterotoxigenic strains, but reflected the amount of LT produced by each strain. These data show that LT and cholera toxin share many common chemical and physical properties, but must be purified by different techniques.
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PMID:Purification and chemical characterization of the heat-labile enterotoxin produced by enterotoxigenic Escherichia coli. 3 93

Incubation of Neurospora crassa conidia with ribonuclease (RNase) A reduces transport of L-phenylalanine by those cells. Under similar conditions, oxidized RNase A, RNase T1, and RNase T2 do not have this effect. Incubation of conidia with active RNase covalently attached to polyacrylamide beads reduces L-phenylalanine transport. This indicates that the site of enzymatic action is at the cell surface. At the lower concentration of enzyme used in this study, incubation with RNase A reduces transport of L-phenylalanine by the general (G) amino acid permease. Increasing the enzyme concentration results in reduction of transport by the neutral aromatic (N)-specific permease. The increased transport activity that accompanies onset of conidial germination is also sensitive to incubation with RNase A. Application of the enzyme to actively transporting cells does not release amino acid transported prior to enzyme addition. Cells cultured on media supplemented with [2-14C] uridine release isotopic activity after RNase A incubation. Analogous treatments with Pronase, RNase T1, RNase T2, or deoxyribonuclease I do not release isotope activity. Pronase treatment does reduce L-phenylalanine transport. Incubation of conidia with RNase A also inhibits germination of those conidia.
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PMID:Effects of ribonuclease A on amino acid transport in Neurospora crassa. 12 24

A procedure is described for the immobilization of monomeric actin so that about 30% of the immobilized protein is competent to bind the monomeric-actin-binding proteins bovine pancreatic deoxyribonuclease I and chicken villin. The intact tertiary structure of the immobilized actin is required to bind these proteins. Using this resin, a method has been developed for the affinity purification of pancreatic deoxyribonuclease I on a reusable actin column. It involves the binding of deoxyribonuclease I to immobilized actin, extensive washing of the column, followed by elution of the bound deoxyribonuclease I with 10 M formamide. After removal of the formamide, the deoxyribonuclease I has a higher specific activity than the starting material and contained no detectable protease or ribonuclease contamination. This preparation should find considerable application in molecular genetic studies where the enzyme is needed free of these particular contaminants. The affinity column should also be useful for the isolation of other, physiologically relevant, monomeric-actin-binding proteins.
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PMID:Preparation of immobilized monomeric actin and its use in the isolation of protease-free and ribonuclease-free pancreatic deoxyribonuclease I. 264 36

The repair of DNA requires the removal of abasic sites, which are constantly generated in vivo both spontaneously and by enzymatic removal of uracil, and of bases damaged by active oxygen species, alkylating agents and ionizing radiation. The major apurinic/apyrimidinic (AP) DNA-repair endonuclease in Escherichia coli is the multifunctional enzyme exonuclease III, which also exhibits 3'-repair diesterase, 3'-->5' exonuclease, 3'-phosphomonoesterase and ribonuclease activities. We report here the 1.7 A resolution crystal structure of exonuclease III which reveals a 2-fold symmetric, four-layered alpha beta fold with similarities to both deoxyribonuclease I and RNase H. In the ternary complex determined at 2.6 A resolution, Mn2+ and dCMP bind to exonuclease III at one end of the alpha beta-sandwich, in a region dominated by positive electrostatic potential. Residues conserved among AP endonucleases from bacteria to man cluster within this active site and appear to participate in phosphate-bond cleavage at AP sites through a nucleophilic attack facilitated by a single bound metal ion.
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PMID:Structure and function of the multifunctional DNA-repair enzyme exonuclease III. 788 81

Research into the use of new genetic markers is difficult and costly, but it is necessary for more accurate criminal individualization and paternity testing as well as for analysis of genetic diseases. Recently, we discovered that human ribonuclease (RNase), deoxyribonuclease I (DNase I) and deoxyribonuclease II (DNase II) are characteristic markers showing genetic polymorphism and useful for forensic investigation. DNase I is particularly well suited to practical use, since it shows a well-balanced gene frequency, a high concentration in several body fluids (blood, sweat, urine, breast milk and semen) and tissues (pancreas, liver and kidney), stability against severe conditions (exposure of test samples to high temperature, high humidity and long-term storage), and easy and accurate detectability.
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PMID:[Discovery of genetic polymorphism of human nucleases]. 895 29

Phenotypic modulation of vascular smooth muscle cells (SMCs) plays a central role in the pathogenesis of atherosclerosis. Natriuretic peptide receptor-C (NPR-C) is highly expressed in vascular SMCs in the experimental arteriosclerotic neointimal area as well as in cultured SMCs, suggesting that increased expression of the NPR-C gene is related to the phenotypic alteration of vascular SMCs. To elucidate the molecular mechanisms and to identify the essential DNA sequences in NPR-C gene expression, a genomic clone containing over 8 kilobases of the 5'-flanking region of the human NPR-C gene has been isolated. Sequence analysis revealed that a number of putative regulatory elements including unusual tandem repeated AP-2-like sequences were observed in the 5'-flanking region. Primer extension and ribonuclease protection analyses revealed that transcription of the human NPR-C gene starts from two major regions. Promoter analysis using deletion constructs in human cells, highly producing NPR-C transcripts, showing that the region (from - 33 to + 13 relative to the transcription start point) had a potential promoter activity suggested that the region from -33 to + 13, containing a pyrimidine-rich stretch composed of four CTTTTT-repeated sequences, is sufficient for the proximal promoter activity. Moreover, three distinct DNA sequences surrounding the transcription start site (P1, from -60 to -33; P2, from + 14 to +40; P3, from +41 to +66) were revealed to be functional as a cis-acting positive enhancer, and a nuclear protein(s) from the human cells was demonstrated to specifically bind to the sequences, respectively. However, promoter analysis has shown that the P2 and P3 sequences could not activate the human NPR-C promoter in a synergistic manner. On the basis of deoxyribonuclease I footprinting analysis showing that a DNA element from +48 to +60 within the P3 sequence is preferentially protected, the P3 sequence appears to contain a potential regulatory element involved in NPR-C gene expression. The present study demonstrated the structure of the 5'-regulatory region of the human NPR-C gene and multiple cis-acting positive sequences closely located around the transcription start points with an important role in regulation of human NPR-C gene expression.
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PMID:Isolation and characterization of the 5'-flanking regulatory region of the human natriuretic peptide receptor C gene. 949 76

This review describes several types of genetic polymorphism, which have recently been identified in human urine in our laboratory, and have also been found in other human body fluids such as blood, saliva and semen. These include uropepsinogen, ribonuclease, deoxyribonuclease I (DNase I), deoxyribonuclease II (DNase II), 43-kDa glycoprotein, alpha-L-fucosidase, glutamate pyruvate transaminase, alpha-2-HS-glycoprotein, transferrin and vitamin D-binding protein. Several substances can be detected more easily in urine than in plasma. The concentrations of uropepsinogen, DNase I and DNase II in blood plasma are too low for analysis, whereas those in urine are high enough for easy typing. In practice, DNase I-polymorphism is one of the most useful genetic markers for practical purposes, because of its higher content in various body fluids including urine, a well-balanced gene frequency, and its easy and accurate detectability. Furthermore, several genetic markers previously identified in blood and/or other forensic samples can be phenotyped reproducibly and easily from the corresponding urine samples. Thus, urine, in addition to the convenience and non-invasive nature of its collection, is by no means inferior to blood as a sample source for typing in the field of forensic science. Biochemical and serological typing of genetic polymorphisms present in human urine could offer useful information to practising forensic biologists for forensic individualization of urine samples.
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PMID:Genetic polymorphisms detectable in human urine: their application to forensic individualization. 954 53

Human angiogenin is translocated to the nucleus of human umbilical vein endothelial cells in a time-dependent manner. Exogenous angiogenin appears in the nucleus in 2 min, reaches saturation in 15 min when 85% of the internalized angiogenin is in the nuclei, and remains associated with the nucleus for at least 4 h. Endothelial cells cultured at low density have a much higher capacity to translocate angiogenin to the nucleus than do those cultured at high density. This observation is consistent with previous findings that both the ability of endothelial cells to proliferate in response to angiogenin and the expression of an angiogenin receptor on the cell surface depend on cell density. Nuclear (125)I-angiogenin is not degraded and is neither spontaneously dissociated nor replaced by unlabeled angiogenin. It is, however, released by deoxyribonuclease I, but not by ribonuclease A, suggesting that angiogenin binds to DNA in the nucleus. These results suggest that in addition to acting as a ribonuclease, angiogenin may play a role in regulating gene expression by direct binding to DNA.
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PMID:Human angiogenin is rapidly translocated to the nucleus of human umbilical vein endothelial cells and binds to DNA. 1064 42