Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The composition of crystalline inclusions and dense bands in cells of broad bean leaves infected with bean yellow mosaic virus was studied by differential enzymatic digestion. Frozen thick sections were prefixed in glutaraldehyde and exposed to proteinases and nucleases, after which ultrathin sections were prepared for electron microscopy. Examination revealed that the crystals were completely digested by pepsin in 30 min, whereas the dense bands remained intact for the first 20 min, and could not be found after longer periods of digestion. When ultrathin sections of tissues embedded in glycol methacrylate were incubated with the enzymes, pepsin digested the crystals; this left only a filamentous residue which did not disappear after further exposure to pepsin or to RNase. Trypsin had the same effect, but was slower and less consistent. The dense bands were entirely digested in thin sections by pepsin and trypsin. Neither inclusion was affected by RNase or DNase in thick or thin sections. These results demonstrate that the crystals and dense bands are composed entirely or primarily of protein, but there is no evidence that they contain nucleic acid.
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PMID:Intracellular characterization of bean yellow mosaic virus-induced inclusions by differential enzyme digestion. 487 90

The architecture of the nucleolus in Allium porum and Triticum vulgare meristematic cells has been investigated by means of digestions with various enzymes. After staining with azure B at pH4, plant nucleoli exhibit lighter regions which, under electron microscopy, correspond to the fibrillar zones characterizing these organelles. Evidence is presented indicating that these latter zones contain coarse convoluted filaments quite similar to the loops first demonstrated by La Cour (24) and which are assumed to originate from the nucleolar-organizing chromosomes. These coarse, 0.2micro wide filaments are remarkably resistant to the action of deoxyribonuclease, ribonuclease, pepsin, trypsin, or of various combinations of these enzymes and, moreover, they show insignificant incorporation of labeled thymidine even after long exposure to this DNA precursor. The clearing action of pepsin on different regions of the nucleolus lends support to the hypothesis that an amorphous material or matrix pervades the mass of this organelle. This effect is particularly striking within the particulate nucleolar zones themselves. Both ribonuclease and trypsin disorganize the RNP (ribonucleoprotein) nucleolar particles. The effect of the latter enzyme on the RNP particles is taken to indicate that they contain proteins particularly susceptible to trypsin which are essential for maintenance of their morphological integrity. Trypsin also interferes with azure B-staining of the nucleolar mass as a whole and, according to radioautographic data, extracts RNA throughout this organelle. Accordingly, the hypothesis is considered that RNA is complexed with proteins not only within the particulate nucleolar portions, as is already well known, but also in the fibrillar zones.
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PMID:The organization of the nucleolus in meristematic plant cells. A cytochemical study. 488 77

Badakhsh, Fred F. (University of Georgia, Athens), and John W. Foster. Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus. J. Bacteriol. 91:494-498. 1966.-Endotoxin-containing precipitates (ECP) were prepared from Brucella abortus strain 19A by aqueous ether extraction followed by ethyl alcohol precipitation. Lysozyme was the most effective of several enzymes tried for detoxification of endotoxin present in the precipitate. Trypsin was shown to reduce mouse lethal toxicity but not rabbit dermal toxicity. Immunological studies of ECP and enzyme-treated ECP demonstrated that lysozyme did not harm the immunogenic property of ECP, whereas heat, ribonuclease, lipase, and proteolytic enzymes had an adverse effect. Serological reactivity of ECP was increased after lysozyme treatment, whereas ribonuclease reduced serological activity.
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PMID:Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus. 495 77

Cell walls isolated from competent streptococci (group H strain Challis) were shown to bind more homologous and heterologous deoxyribonucleic acid (DNA) than noncompetent walls. Heat- and alkali-denatured DNA was not bound by either wall preparation. Pretreatment of cell walls with cetyltrimethylammonium bromide sharply increased the binding of DNA but did not increase transformation of whole cells. Pretreatment of the walls with either sodium dodecylsulfate, deoxyribonuclease and ribonuclease, or with crude competence-provoking factor did not affect the binding of DNA. Antiserum prepared against whole competent cells completely blocked transformation and also inhibited DNA binding to competent cell walls. Adsorption of this antiserum with competent Challis cells removed its blocking action for both binding and transformation. Pretreatment of walls with trypsin and Pronase destroyed their ability to bind DNA. Trypsin treatment also blocked transformation in whole cells. The transforming activity of DNA bound to cell walls was found to be protected from deoxyribonuclease action. Significant differences were observed in the arginine, proline, and phenylalanine content of competent and noncompetent walls. With few exceptions, the amino acids released from competent cell walls by trypsin were several-fold greater than from noncompetent walls. The results indicate that (i) two binding sites exist, one in competent cells only and essential for subsequent transformation, and a second, present in all cells, which is not involved in transformation; (ii) both sites are protein in nature; (iii) the transformation site is blocked by antibody; and (iv) the competent cell wall possesses tryptic-sensitive protein not present in the noncompetent wall.
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PMID:Binding of deoxyribonucleic acid by cell walls of transformable and nontransformable streptococci. 510 95

1. Pancreatic ribonuclease in dilute EDTA has been shown to condition rough-microsomal membranes from adult rat liver to accept exogenously added rat liver polyribosomes in vitro at 0-4 degrees C. Treated smooth membranes would not significantly interact with polyribosomes. 2. The conditioning process decreased the membrane RNA content and removed polyribosomes from vesicle surfaces as viewed electron-microscopically. 3. Binding to these conditioned membranes was shown to be uninfluenced by changes of temperature (0-37 degrees C) and pH (6.9-7.8) or the presence of cell sap, but was inhibited by increasing the concentration of potassium chloride. 4. Possession of a polyribosome-binding capacity by conditioned rough membranes was not dependent on adventitious materials that could be dislodged by high ionic strengths. 5. Trypsin treatment under mild conditions destroyed the binding capacity of ribonuclease-conditioned rough membranes. 6. A 2-10S residual RNA was recovered from ribonuclease-conditioned membranes, but its partial removal had no effect on the capacity of membranes to accept polyribosomes. However, some role for this residual RNA in attaching polyribosomes could not be discounted. 7. Evidence is considered that polyribosome-binding sites are intrinsic features of conditioned membranes isolated from rough-microsomal fractions, and that long-range ionic bonding is a primary factor in polyribosome interaction with these binding sites.
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PMID:The association in vitro of polyribosomes with ribonuclease-treated derivatives of hepatic rough endoplasmic reticulum. Characteristics of the membrane binding sites and factors influencing association. 515 23

1. Trypsin and ribonuclease were filtered through dextran gel (Sephadex G-100) columns in the absence and presence of their respective substrates. In the presence of their high-molecular-weight substrates the enzymes emerged earlier from the columns. This appeared to be due to the reversible formation of specific enzyme-substrate complexes. 2. The possibility of separation of an enzyme from other proteins with similar molecular weights was demonstrated with trypsin and cytochrome c in the presence of casein.
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PMID:Dextran-gel filtration of enzymes in the presence of their high-molecular-weight substrates. 593 53

The concentration of immunoreactive protein in the cytosol of L1210 cells measured using a specific radioimmunoassay for dihydrofolate reductase was substantially greater than the concentration of active enzyme which was measured by the binding of [3H]methotrexate. When the cytosol was subjected to gel filtration, two immunoreactive proteins were separated, a high-molecular-weight (Mr 318,000) protein which did not have catalytic activity and which did not bind [3H]methotrexate and a smaller protein (Mr approximately 20,000) which did reduce [3H]folic acid to tetrahydrofolate and did bind [3H]methotrexate. The nonfunctional high-molecular-weight protein neutralized the inhibitory effect of the antiserum on active dihydrofolate reductase. There was no spontaneous disaggregation of the big species into smaller subunits nor did 8 M urea alone, dithioerythritol alone, boiling with a mixture of 8 M urea and dithioerythritol, or RNase alter its apparent molecular weight. Trypsin, however, digested both the nonfunctional and active immunoreactive forms of the enzyme. Isoelectric focusing of the cytosol separated two nonfunctional immunoreactive isoproteins, each having the same isoelectric points as the two active isoenzymes of dihydrofolate reductase (pls of 8.0 and 8.5). Studies in rapidly replicating and stationary-phase L1210 cells showed that the concentration of the nonfunctional immunoreactive protein increased rapidly, reaching a peak on Day 2 of log growth at which time active enzyme was at a nadir, and then decreased rapidly, reaching a nadir on Day 4, at which time active enzyme was at a peak. The identical isoelectric points for the inactive and active immunoreactive proteins and the reciprocal concentration of each form in logarithmically growing cells suggest that the immunoreactive large species may be a precursor of the active enzyme.
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PMID:Identification of a high-molecular-weight nonfunctional protein in L1210 leukemia cells with common antigenic determinants to dihydrofolate reductase. 618 48

Ribonuclease (RNase) activity from human serum appears as multiple zones of activity following isoelectric focusing in thin layer polyacrylamide gel. At least one but not all of these zones is cross reactive with rabbit antibovine pancreatic RNase A antiserum. Treatment of serum or partially purified serum RNase with neuraminidase reduces the complexity of the serum RNase banding pattern to a major band which focuses at a pH of 9.5 or greater and a minor zone of activity which focuses at about pH 6.0-6.2. Trypsin does not affect the pattern. Thus, sialic acid residues account for a large portion of the heterogeneity of human serum RNase. Neuraminidase treatment is requisite for evaluating RNase from serum and certain other sources.
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PMID:Sialic acid residues contribute to the heterogeneity of human serum ribonuclease: demonstration by isoelectric focusing and neuraminidase treatment of serum. 647 25

1. RNase Ms, a base non-specific RNase from Aspergillus saitoi was reduced and carboxymethylated (RCM-RNase Ms). RCM-RNase Ms was hydrolyzed with trypsin, and the trypsin digests were then treated with chymotrypsin. Trypsin digests were also treated with Staphylococcus protease and with chymotrypsin, separately. 2. By the analyses of the amino acid sequences of the peptides formed, the alignment of these peptides in RCM-RNase Ms was determined. 3. From the digest of heat-denatured RNase Ms with Bacillus subtilis protease, two peptides containing disulfide bridges were isolated. From the analysis of these two peptides, the locations of the bridges were determined. 4. The amino acid sequence of RNase Ms was compared with those of RNase T1 (Asp. oryzae, guanine specific), RNase U1 (Ustilago sphaerogena, guanine specific) and RNase U2 (Ustilago sphaerogena, purine specific). There are very similar sequences between these for RNases irrespective of their differences in base specificity. These were, in RNase Ms, tripeptide sequence containing His39 (Tyr-Pro-His), the tetrapeptide containing Glu57 (Glu-Tyr-Pro-Ile), the hexapeptide containing Arg76 (Asp-Arg-Val-Ile-Phe-Asp) and the hexapeptide containing His 91 (Ile-Thr-His-Thr-Gly-Ala). The other sequences common for all four RNases are Tyr67, Phe100, and Cys103 in RNase Ms. Since among these peptides His39, Glu57, His91, and Arg76 in RNase Ms corresponded to His40, Glu58, His92, and Arg77 in RNase T1 which are known to be involved in the active site of RNase T1, the possible role of these amino acids in the active site of RNase Ms is discussed. 5. The sequence similarity of RNase Ms to that of RNase T1 was about 60% and to those of RNase U1 and RNase U2 was about 30%. 6. The details of the experimental evidence used to elucidate the amino acid sequence of RNase Ms are described in the supplemental miniprint.
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PMID:Primary structure of a minor ribonuclease from Aspergillus saitoi. 709 2

Antigens A and B, shown to be associated with the progestagen-dominated human endometrium, were partly purified and their properties studied. The antigens were recovered in the crude nuclei, the heavy particulate fraction and cytosol of decidua-rich tissue from early pregnancy. The antigens in cytosol were enriched by a combination of Concanavalin A-Sepharose chromatography and polyacrylamide gel electrophoresis. The immunological reactivity of the antigens after partial purification by Concanavalin A-Sepharose chromatography was retained after 30 min exposure to 4-85 degrees C at pH 7.4, or after 2 h to pH 2-12 at 22 degrees C. Trypsin, but not pepsin, RNase, DNase or neuraminidase, completely destroyed immunological reactivity of both antigens. The apparent molecular weight of both antigens determined by filtration on Sephadex G100 was 48 000. The isoelectric point of both antigens was approximately 4.9. The antigens were not immunologically related to transferrin, ceruloplasmin, alpha-1-antitrypsin, ferritin, uteroglobin, alpha-fetoprotein, human chorionic gonadotrophin, pregnancy-associated plasma proteins or pregnancy zone protein. Furthermore, the antisera to Antigens A and B did not react with the decidual cytosol of pregnant baboons or of pseudopregnant rats.
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PMID:Properties of the progestagen-dependent protein of the human endometrium. 743 Dec 86


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