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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The differentiation of rat liver lysosomal acid phosphatase, acid ATPase, acid phosphodiesterase, acid ribonuclease, and acid deoxyribonuclease was studied by isoelectric focusing. To prevent autolytic digestion, inhibitors of cathepsins and neuraminidase were used. The proportion of acidic forms of acid phosphatase, acid ATPase and acid phosphodiesterase was increased by the use of extraction medium containing 0.05% Triton X-100. To investigate the identity of acid ATPase and acid phosphodiesterase, the relative activities among the multiple forms of these enzymes, the acid phosphodiesterase/acid ATPase ratio at each activity peak, and the degree of enzyme inhibition by p-chloromercuriphenyl sulfonic acid were estimated. The results suggest that acid ATPase is not identical with acid phosphodiesterase. With extraction medium free of Triton X-100, acid ribonuclease appeared in two forms. However, in addition to these forms, a new form of this enzyme with a more acidic pI (4.22) emerged when extraction medium containing 0.05% Triton X-100 was used. The major peak of acid deoxyribonuclease with pI=8.40-9.39 was obtained regardless of the extracting method.
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PMID:An isoelectric focusing study of acid phosphohydrolases in rat liver lysosomes. 2 87

Binding sites for prolactin were identified in a plasma-membrane-enriched fraction isolated from livers of mature female rats. 125I-labelled sheep prolactin prepared by the lactoperoxidase procedure retained the same molecular integrity and binding affinity as the native hormone at physiological pH. The receptors bound prolactin from different species, whereas non-lactogenic hormones were not bound. The binding of 125I-labelled sheep prolactin was activated equally by bivalent and univalent cations, bivalent cations exerting their maximal effect at much lower concentrations. The association of 125I-labelled sheep prolactin with the receptor was a time- and temperature-dependent process. Partial dissociation was detected. The binding of 125I-labelled sheep prolactin was strongly influenced by pH, with an optimum observed at pH 6.5. Receptor activity was destroyed by Pronase and phospholipase C, whereas neuraminidase increased binding. Treatment of the membranes by ribonuclease and deoxyribonuclease did not affect the binding. Binding of 125I-labelled sheep prolactin was inhibited by p-chloromercuribenzoic acid, dithiothreitol and by brief exposure to high temperatures. Scatchard analysis of the binding of 125I-labelled sheep prolactin to receptors indicated that prolactin has a high affinity for its receptor. Binding of prolactin to liver membranes showed some properties different from those observed with mammary cells. Binding by these tissues differed in pH optimum, in effects of ions, and in response to neuraminidase.
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PMID:Characterization of prolactin binding by membrane preparations from rat liver. 3 84

An antigen was detected in pooled human nephroblastomas using antiserum prepared in rabbits against an ethylemediaminetetra acetic acid (EDTA) extract of the tumors. This antigen was not found in normal human plasma or kidney extracts, and was not related to the ABO or Forssman blood groups. The antigen was detected in extracts of cultured nephroblastoma cells, but was not present in extracts of normal human fetal kidney cell cultures. The antigen is believed to be present at the cell surface, as cell viability was not significantly lowered during the extraction procedure. A reaction of complete identity was demonstrated by Ouchterlony double diffusion experiments with this antigen and purified bovine fetuin. The antigen was not found in extracts of human fetal spleen, thymus or kidney, nor in human fetal serum. Furthermore, the antigen does not possess determinants in common with the human alpha-fetoprotein of hepatomas, nor was it detected in human renal clear cell carcinoma. Initial characterization of the antigen showed it to be nondialysable, not sedimentable at 100,000 times g for 2 h, stable to repeated freeze-thawing and to incubation at 56 degrees C for 1 h, and water soluble over a wide pH range. The antigen was susceptible to digestion with pronase and trypsin and possibly hyaluronidase, but not to ribonuclease or neuraminidase. The protein portion is therefore of major importance to the structural integrity of this antigen. The relationship between this antigen and other abnormal materials reported previously in nephroblastoma patients is being studied.
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PMID:A fetuin-like antigen from human nephroblastoma. 5 Feb 93

The ultrastructural study of liver tissues from 38 patients with type B viral hepatitis consistently showed the presence of hepatitis B core antigen of 21-25 nm size in the liver cell nuclei and to a lesser extent in the cytoplasm. This finding and the demonstration of the tubular form of hepatitis B surface antigen in the proliferative degranulated endoplasmic reticulum constituted the etiologic criterion for the diagnosis of the disease. The double-shelled Dane-like particles were frequently found in association with the tubular form of the surface antigen. The core particles were found in the protoplasmic processes of hepatocytes and this correlated with the immunofluorescent microscopic findings that the antigen may be shed into circulation with the protoplasm. The core antigen was found to resist digestion by various enzymes such as protease, DNase, RNase, phospholipase C, lipase, lysozyme, diastase, neuraminidase and hyaluronidase, all of which did not destroy the immunoreactivity as demonstrated by immunoelectron and immunofluorescent microscopy. Similarly, sodium dodecyl sulfate, Tween 80 and mercaptoethanol also had no effect. The formalin-fixed paraffin-embedded liver tissue sections could be treated with protease to facilitate the immunofluorescent staining for the core antigen in tissue.
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PMID:Structural and immunoreactive characteristics of hepatitis B core antigen. 5 6

By application of electron cytochemical techniques to cerebellar tissue, the presence of proteoglycans was demonstrated at the axoplasmic matrix of mossy fiber endings. Blocks of glutaraldehyde (G) fixed mouse cerebellum were processed according to the following procedures: a) Some pieces of tissue were post-fixed in osmium tetroxide, dehydrated by ethanol and embedded in araldite. b) Other pieces were sectioned to 30 mum thick and then immersed in Alcian blue solution pH = 2.7 followed by osmium tetroxide fixation, dehydrated and embedded in araldite (GABOUL procedure). c) Parallel slices of (b) previous to Alcian blue immersion were washed and incubated in either methanol-HCl, neuraminidase, ribonuclease or testicular hyaluronidase with their respective controls. d) Other blocks of G fixed tissue without any other treatment and fixation were dehydrated and embedded in araldite. Ultrathin sections of a, b and c were doubly stained with uranyl acetate and lead citrate while ultrathin sections of (d) were stained with the osmium coordination compound Os-DMEDA. The electron microscopic study revealed at the presynaptic axoplasm of mossy fiber rosettes, the presence of a GABOUL and Os-DMEDA positive electron dense material surrounding synaptic vesicles and continuous with presynaptic dense projections. This material which coincides with cytonet distribution was resistant to neuraminidase and ribonuclease and sensible to hyaluronidase and carboxymethylation. These findings permit us to conclude that the axoplasmic material of mossy fiber endings is constituted by proteoglycans in which hyaluronic acid and chondroitin 4-and/or 6-sulphate are present. The probable importance of these proteoglycans in synaptic mechanisms is also discussed.
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PMID:Electron microscopic demonstration of hyaluronidase sensible proteoglycans at the presynaptic area in mouse cerebellar cortex. 6 92

Circulating M antigen, previously described in urine from patients infected by Schistosoma mansoni, was shown in serum from infected patients, using human anti-M immune serum with immunodiffusion and immunoelectrophoretic analyses. This antigen was also shown to be present in the serum and urine from infected hamsters, in the urine from infected rabbits and in the serum from infected mice. Generally, it appeared on day 20 after infection. M antigen was specific for the genus Schistosoma and for the immature and adult worm stage. Its electrophoretic migration was cathodic. The molecular weight of urinary M antigen was around 45,000 daltons. The M antigen was thermostable, soluble in trichloroacetic acid, and contained no lipid component. It was hydrolyzed by protease, ribonuclease, amylase or neuraminidase, but was destroyed by sodium metaperiodate. All these properties betoken the polysaccharidic nature of M antigen.
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PMID:Further studies on the circulating M antigen in human and experimental Schistosoma mansoni infections. 10 64

KCl extract from rat kidney, rat liver, and Morris hepatomas inhibited [3H]thymidine incorporation into cultured cells. Tissues came from male inbred BUF rats. The most pronounced inhibition was achieved with the kidney extract. Protein synthesis was not inhibited during a 24-hour exposure of the cells to the inhibitor. Incorporation of [3H]deoxycytidine was inhibited, as was cell growth, when the kidney KCl extract was present for several days. [3H]thymidine incorporation was inhibited almost immediately after the addition of the extract. The inhibition was reversible. Regular [3H]thymidine incorporation was restored 24 hours after removal of the inhibitor, which was neither arginase nor a thymidine-degrading enzyme. The inhibitor was stable to heat (80 degrees C for 10 min) and resistant to trypsin, pronase, DNase, and RNase. Exposure of the extract to proteolytic enzymes, hyaluronidase, and neuraminidase resulted in a loss of inhibitory activity only after extensive dialysis of the treated extract. The inhibitor appeared to be a mucoprotein in which the carbohydrate moiety may be responsible for the inhibition. The KCl extract also inhibited RNA synthesis and DNA synthesis by the de novo pathway. The inhibition of phosphorylation of thymidine, however, appeared to be the primary action of the inhibitor.
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PMID:Inhibition of tritiated thymidine incorporation in cultured cells by rat kidney extract. 15 53

We have perfused isolated rat livers with hypocalcemic (4.4 mg 100 ml) Krebs-Ringer bicarbonate albumin buffer. After 15 min of perfusion, a substance appeared in the perfusate which decreased rat renal adenylate cyclase activation by parathyroid hormone (PTH). The material in the perfusate was purified greater than 50,000-fold by Bio-Gel P-10 chromatography. The purified antagonist decreased the activation of rat renal cortical adenylate cyclase by PTH, glucagon, and epinephrine 75 to 100%. Concentration response curves for each of the hormones indicated a noncompetitive interaction of the inhibitor with the hormone. The inhibition was not species-specific, as the activation of the parathyroid hormone-responsive adenylate cyclase in cat renal cortex was also abolished by the inhibitor from the perfused rat liver. The inhibitor is a peptide, Mr equal to similar to 1000, which is heat-stable, acid-stable, alkai-labile, and is destroyed by trypsin, leucine aminopeptidase, and elastase. It is not destroyed by phosphodiesterase, 5'-nucleotidase, alkaline phosphatase, neuraminidase, RNase, or phospholipase A. The inhibitor is not produced by isolated rat livers perfused with normocalcemic perfusion media. It is unclear whether the peptide is synthesized by the liver or whether it is a breakdown product of a larger peptide or protein in the liver. This is the first reported peptide inhibitor of adenylate cyclase.
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PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

Mouse 3T3, Simian virus 40 transformed 3T3 cells (SV3T3) and two SV3T3 lines showing reversion of their transformed phenotype (Rev 3 and Rev 5) have been studied with respect to electrophoretic mobilities and colloidal iron hydroxide (CIH) binding density visible by electron microscopy, before and after incubation with neuraminidase or ribonuclease. The results show that, in general, the marked changes in both sets of surface parameters associated with transformation are largely reversed in the Rev 5 revertant, and only partially reversed in the Rev 3 line. It was also observed that, in common with Ehrlich ascites tumor (EAT) cells examined previously, the densities of CIH-particles bound over the microvilli of all the cell types was 1.5 to 2.7 times higher than those bound to the spaces between them. In contrast to the EAT cells, the higher density of CIH particles bound over the microvilli was not due to neuraminidase-sensitive binding sites.
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PMID:Some electrical properties of the peripheries of murine 3T3 cells with respect to viral transformation and reversion. 17 59

The ascites form of a chemically induced guinea pig hepatoma, line-10, was resistant to killing in vitro by xenogeneic antibody and guinea pig complement. Pretreatment of line-10 cells with certain proteolytic enzymes rendered tham susceptible to the killing action of antibody and guinea pig complement. The effects of enzyme pretreatment were dependent on enzyme concentration, temperature, and could be blocked by addition of competitive or non-competitive inhibitors. The effect of the enzyme treatment could reversed by incubating the treated cells at 37 degrees C (but not at 0 degrees C), in the absence of the enzyme. Effective enzymes included ficin, bromelain, pronase, elastase, papain, trypsin, collagenase, lipases type I and type VI, and the neuraminidase preparation isolated from Clostridium perfringens. The activity of the lipase preparations and the neuraminidase preparation isolated from Clostridium perfringens appeared to be caused by proteolytic enzyme contamination. Enzyme preparations that proved ineffecitve in rendering the line-10 cells sensitive to killing by antibody and guinea pig complement included DNase, RNase, beta-glucuronidase type 6A or type B10, hyaluronidase type V or type VI, and pectinesterase.
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PMID:Lysis of tumor cells by antibody and complement. VI. Enhanced killing of enzyme-pretreated tumor cells. 17 70


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