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)

1. Lysosome-rich fractions from rat liver were subjected to several disruptive procedures: osmotic lysis or freezing and thawing in different media, shearing forces in a high-speed blender, treatment with Triton X-100. 2. The soluble and particulate phases were then separated by high-speed centrifugation and assayed for their content of acid phosphatase, beta-galactosidase, beta-N-acetylglucosaminidase, acid proteinase, acid ribonuclease, acid deoxyribonuclease and protein. 3. The degree of elution of these hydrolases appeared to depend on both the enzyme species and the treatment. The resulting patterns of solubilization were rather complex, so that a clear-cut discrimination between soluble and structure-bound enzymes could not always be traced. 4. Although only beta-galactosidase was readily solubilizable after all treatments, acid proteinase could also be extensively eluted from the sedimentable material in the presence of EDTA and acid phosphatase was fully extracted by Triton X-100. On the other hand, considerable proportions of the other activities could not be solubilized by any of the procedures used. 5. In other experiments, the adsorbability of hydrolases on subcellular structures was investigated by measuring the partition between sedimentable particles and soluble fraction of solubilized enzymes added to ;intact' liver homogenates. 6. Large proportions of acid proteinase, ribonuclease and deoxyribonuclease, and almost all of beta-N-acetylglucosaminidase, were found to be adsorbed on the particulate material.
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PMID:Studies on the structure-bound sedimentabolity of some rat liver lysosome hydrolases. 511 7

At short intervals after the intravenous administration of oestradiol-17beta, diethylstilboestrol, testosterone or saline control solution to ovariectomized rats, highly purified lysosome samples were prepared in substantial yield from preputial glands, sex accessory organs rich in these organelles. The preparations were essentially devoid of mitochondrial contamination. Exposure in vivo to doses of these hormones varying from 0.1 to 5mug/100g body wt. provoked dose-dependent labilization of the lysosomal membrane surface, as evidenced by significantly diminished structural latency of several characteristic acid hydrolases, including acid phosphatase, beta-glucuronidase and acid ribonuclease II, when such preparations were subsequently challenged in vitro with autolytic conditions, detergent or mechanical stress. Enhanced lytic susceptibility induced by hormone pretreatment was occasionally detectable in the initial preparation without further provocative stimuli in vitro. Comparable results were obtained with the corresponding fractions of uterus, despite the more limited concentration of lysosomes in this steroidal target organ. By the present criteria oestradiol-17alpha was essentially inert, even in a dose 25 times that effective for its active beta-epimer (<0.1mug/100g body wt.). Pretreatment with diethylstilboestrol exerted substantial membrane-destabilizing influence in preputial-gland lysosome samples from orchidectomized rats. Moreover, administration of testosterone to gonadectomized animals resulted in essentially equivalent dose-dependent augmentation of lysosomal enzyme release in preputial-gland preparations of either sex. The membrane stability of lysosome-enriched preparations from uterus, on the other hand, was unaffected by testosterone pretreatment. The sensitivity, specificity and selectivity of the lysosomal response to sex steroids provide evidence for the physiological significance of this phenomenon as a general mechanism for mediation of secondary biochemical transformations in the hormone-stimulated target cell.
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PMID:The lysosomal membrane complex. Focal point of primary steroid hormone action. 512 5

We report the effects of abscisic acid and auxin (alpha-naphthalene acetic acid) on regulation of enzyme synthesis during senescence of leaf sections of Rhoeo discolor Hance. Abscisic acid always accelerates the onset of and enhances the magnitude of the increase in activity of acid phosphatase; this is followed by an acceleration of the onset of a rapid increase in free space.RNase activity increases 2- to 5-fold after cutting of leaf sections. Abscisic acid increases RNase activity and inhibits the rate of incorporation of uridine and leucine in leaf sections removed from plants grown under stress but not favorable conditions. Auxin inhibits the increase in RNase and acid phosphatase and suppresses the effects of abscisic acid. The increase in activity of RNase and acid phosphatase is inhibited by inhibitors of RNA and protein synthesis. This and other evidence suggests that the increases in hydrolase activity could result from new enzyme synthesis. The possible significance of the results in respect of hormonal regulation of enzyme activity and senescence is discussed.
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PMID:Control of ribonuclease and acid phosphatase by auxin and abscisic acid during senescence of Rhoeo leaf sections. 550 Feb 7

Rat mammary tumours induced by 7,12-dimethylbenz[a]anthracene can undergo repeated growth and regression during successive pregnancies. In a 10-day period after birth about half of the tumours regressed 50% or more. The concentrations of the lysosomal enzymes increased in regressing mammary tumours to the following multiples of the initial values: beta-glucuronidase, 7.7; beta-galactosidase, 3.9; cathepsin, 2.9; acid ribonuclease, 2.1; arylsulphatase A, 1.5; acid phosphatase, 1.4. In contrast, several non-lysosomal enzymes failed to increase. Activities in the post-partum uterus increased to the following multiples of the initial values: beta-glucuronidase, 5.8; cathepsin, 5.5; acid ribonuclease, 4.3; beta-galactosidase, 2.2; acid phosphatase, 1.8. Arylsulphatase A in the post-partum uterus decreased significantly, suggesting a non-lysosomal distribution or a special function related to pregnancy. No other significant changes were observed in the lysosomal or non-lysosomal enzymes in the hormone-independent liver or hormone-dependent normal mammary gland. The ratio of free to bound arylsulphatase A and acid ribonuclease decreased slightly 1-3 days after birth because of problems in homogenizing the tumours. At days 4-8, however, there was a dramatic increase in the ratio of the free to bound activities. The results can be explained in terms of the lysosomal theory of intracellular digestion.
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PMID:Lysosomal enzyme changes in growing and regressing mammary tumours. 576 57

1. An investigation has been made of the changes occurring in lysosomal enzyme activities during the early development of experimentally produced liver injury in the rat. Three enzymes have been studied: acid phosphatase, acid ribonuclease and beta-glucuronidase. Four different methods of inducing liver injury have been used: administration of carbon tetrachloride, thioacetamide, dimethylnitrosamine and the fungal toxin sporidesmin. 2. The majority of the data presented concern alterations produced by carbon tetrachloride. Despite the extensive central necrosis and accompanying fat accumulation which this poison produced in the liver, only small changes in the activity and latency of lysosomal enzymes could be detected. In the early (pre-necrotic) period of injury these changes were insignificant. At a late stage of injury, when extensive centrilobular necrosis was present, there were indications of lysosomal rupture. 3. The results obtained with the other three hepatotoxins were similar to those described for carbon tetrachloride in that no evidence of early lysosomal rupture was obtained during the pre-necrotic period. It is concluded that lysosomes probably play no role in the early development of the four types of liver injury studied but, instead, are involved in later scavenging processes.
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PMID:Changes in lysosomal enzymes in acute experimental liver injury. 583 87

1. An homogenate of bovine adrenal medulla contains significant amounts of six acid hydrolases: acid ribonuclease, acid deoxyribonuclease, cathepsin, acid phosphatase, beta-glucuronidase and arylsulphatase. Most of the activity of each enzyme could be sedimented in the large-granule fraction at 242,000 g-min.2. Differential centrifugation indicated the presence of three populations of particles, which sedimented at slightly different rates; these are, in order of decreasing sedimentation rate, mitochondria, particles containing the acid hydrolases, and chromaffin granules.3. The three types of particle could be separated by ultracentrifuging the large-granule fraction in a sucrose density gradient. Most of the activity of each hydrolase was recovered in a layer intermediate between those formed by mitochondria and chromaffin granules.4. The large-granule fraction therefore contains particles which are defined by their enzyme content as lysosomes.5. Highly purified chromaffin granules, containing less than 5% of the activity of each acid hydrolase, were obtained from the gradient.
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PMID:The localization of lysosomal enzymes in chromaffin tissue. 594 47

Activities of three lysosomal enzymes--acid RNase. N-acetyl-beta-D-glucosaminidase and acid phosphatase--were determined during the growth cycles of WI-38 and HeLa cells, as well as in radiation-arrested WI-38 cells. In confluent and growth-arrested cultures of WI-38 cells, the lysosomal RNase increased six- to sevenfold; glucosaminidase, four- to fivefold; and phosphatase, two- to threefold. In HeLa cells, the lysosomal enzymes also increased in confluent cultures, but less than twofold; and the RNase level increased only transiently. In both WI-38 and HeLa cells, the rate of RNA breakdown also increased as cultures approached confluency. The rate of turnover of RNA, like the level of acid RNase, was higher in WI-38 cells than in HeLa cells (4 d half-life compared to 8 d). The increase in acid RNase could be prevented by incubation of cells in NH4Cl, but the rate of turnover in the presence of NH4Cl increased just as much when cells became confluent or stopped growth. The content of acid RNase could be changed more than 10-fold without altering the rate of RNA turnover. It is suggested that the increase in enzyme level is more important for possible autophagy or increased digestion of engulfed RNA, rather than for normal RNA turnover, when growth stops.
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PMID:Lysosomal enzyme activities and RNA turnover rates in growing and nongrowing WI-38 and HeLa cells. 617 May 71

The effect of methylnitrosourea (MNU) on cerebellar and cerebral DNA, RNA, protein, lysosomal enzymes (acid DNase, RNase, phosphatase, and beta-glucuronidase), and 2',3'-cyclic nucleotide 3'-phosphohydrolase (2',3'-CNPase) activities was studied in rats from birth through 12 days of age. Subcutaneous injection of MNU in a dose of 0.625 mmol/kg caused a suppression of increase in weights and content of DNA, RNA, and protein of cerebellum, but no changes in those of the cerebrum or in body weight. Ratios of protein and RNA to DNA were substantially elevated by MNU in the cerebellum but not in the cerebrum. Acid DNase and acid RNase activities of MNU-treated rats were significantly elevated beyond the increase of these activities in controls in the cerebellum, but no change in these activities by MNU was observed in the cerebrum. A slight elevation in acid phosphatase activity was observed in the cerebellum but not in the cerebrum after MNU pretreatment. Beta-glucuronidase and 2',3'-CNPase activities were not changed in the cerebellum or in the cerebrum. These results suggest that in the developing brain, especially in the cerebellum at the mitotic stage, MNU caused cell damage and inhibited cell mitosis.
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PMID:Cytotoxic effects of methylnitrosourea on developing brain. 619 99

Distribution of ribonuclease (RNAase), acid phosphatase (acid Ph-ase) and beta glucuronidase (BGU) between the granule, cytosol-soluble and post-granule fractions in normal human granulocytes and in granulocytes of chronic granulocytic leukemia (CGL) was studied. CGL granulocytes were found to display relative RNAase activity 1.2 times higher, relative acid Ph-ase activity 2.5 times higher than normal granulocytes. The granule fraction of CGL granulocytes showed 1.4 times higher relative RNAase activity but 0.87 times lower acid Ph-ase activity and the same BGU activity as normal granulocytes. On the other hand, the supernatant soluble fraction of CGL granulocytes showed 4.4 times higher relative RNAase activity, 1.2 times higher relative acid Ph-ase activity and BGU 2.2 times higher than in cytosol soluble fraction of normal granulocytes. Thus, cytosol soluble fraction of CGL granulocytes show a relative activity of the lysosomal enzymes studied which is remarkably higher than in normal granulocytes. The percentage distribution of RNAase, acid Ph-ase and BGU showed that CGL granulocytes contain only 36% of total RNAase activity versus 46% of that in normal ones. On the other hand, CGL granulocytes in cytosol soluble fraction will contain 48% of total RNAase versus 29% of total RNAase in cytosol of normal granulocytes. The isoenzyme profiles of RNAase of granule fractions were similar in normal and CGL granulocytes, while the RNAase isoenzyme profiles of cytosol fractions were different for normal and CGL granulocytes, indicating that some essential part of CGL granulocyte cytosol RNAase differs from RNAase contained in granules and in cytosol of normal granulocytes.
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PMID:Differences in distribution of ribonuclease isoenzymes in cytosol and granules in normal human granulocytes and in granulocytes of patients with chronic granulocytic leukemia (CGL). 620 Mar 92

Bloodstream forms of Trypanosoma brucei have been screened for the presence of enzymes that could serve as markers for the plasma membrane, flagellar pocket, lysosomes, endoplasmic reticulum and Golgi apparatus in order to study the subcellular organization of the digestive system of the parasite. Acetylesterase, acid DNase, acid phosphatase, acid phosphodiesterase, acid proteinase, acid RNase, alanine aminotransferase, galactosyl transferase, alpha-glucosidase, inosine diphosphatase and alpha-mannosidase were partially characterized and their assays optimized for pH-dependent activity, linearity of reaction with respect to incubation time and enzyme concentration, and the effect of inhibitors and activators. The association of these enzymes with particulate material and the presence of structural latency were investigated. Acid proteinase and alpha-mannosidase are particle-bound and latent in cytoplasmic extracts; they can be activated and solubilized in part by Triton X-100. Similar results were obtained for acid phosphatase, acid phosphodiesterase and inosine diphosphatase. Neutral alpha-glucosidase, though partly sedimentable, does not show latency and is readily solubilized by the detergent. Galactosyl transferase is firmly membrane-bound even in the presence of 0.1% Triton X-100. Cell fractionation by differential centrifugation and density equilibration on sucrose gradients revealed that both alpha-mannosidase and acid proteinase are associated with organelles that band at a density of about 1.20 g/cm3. Inosine diphosphatase, galactosyl transferase, acid phosphatase and acid phosphodiesterase sediment predominantly as microsomal constituents equilibrating at densities between 1.13 and 1.15 g/cm3. In addition, inosine diphosphatase and galactosyl transferase exhibit considerable activity at higher densities (1.18-1.25 g/cm3). Neutral alpha-glucosidase is mainly recovered in the nuclear and microsomal fraction; its particulate part equilibrates as a single band at rho = 1.22 g/cm3. Acetylesterase and acid DNase are largely soluble, whereas acid RNase does not produce distinct sedimentation and banding profiles. In intact cells, neutral alpha-glucosidase and acid phosphatase appear to be highly accessible to their substrates. It is tentatively concluded that (a) acid proteinase and alpha-mannosidase are lysosomal enzymes, (b) acid phosphatase and acid phosphodiesterase are associated with the flagellar pocket and part of the former enzyme probably with the endoplasmic reticulum, (c) galactosyl transferase is a constituent of the Golgi apparatus, and (d) alpha-glucosidase may serve as a marker for the plasma membrane. Inosine diphosphatase may also be derived from the latter structure.
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PMID:Subcellular fractionation of Trypanosoma brucei bloodstream forms with special reference to hydrolases. 624 76


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