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)

Five ribonuclease activities, separable by polyacrylamide gel electrophoresis, have been detected in erythroid bone marrow cells from anaemic rabbits. Their intracellular distribution has been investigated and compared with that of the ribonucleases in reticulocytes. Both the acid and alkaline ribonuclease activities of reticulocytes are much lower (30--50 fold) than those of bone marrow erythroid cells. The most marked decrease in enzyme activity occurs in the fractions containing ribosomes and mitochondria plus lysosomes. In these subcellular organelles there was also a qualitative change in the ribonuclease electrophoretic pattern, whereas the cytosol enzymes of marrow erythroid cells and reticulocytes remained largely unchanged. Several ribonucleases released from reticulocyte membranes with urea were similar to those present in the lysosomal plus mitochondrial fraction, as shown by detection of enzyme activity after polyacrylamide gel electrophoresis. The decline in ribonuclease activity was found to begin in the orthochromatic cells, which have a highly condensed nucleus and are no longer active in DNA and RNA synthesis, and to coincide with a decrease in acid phosphatase activity and loss of lysosomes.
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PMID:Intracellular distribution of ribonuclease activity during erythroid cell development. 1 51

In an effort to develop a sensitive and specific method for detecting human prostatic cancer at early stages, we have studied the isoenzyme patterns of acid phosphatase in patients' sera as well as in benign hypertrophic and cancerous prostatic tissues using isoelectric focusing techniques. At least eight acid phosphatase isoenzymes at pI 4.1-5.5 could be observed. The sera with highly elevated acid phosphatase activity generally contained more isoenzymes with pI values of 4.5-5.0. The purified acid phosphatase isolated from benign hypertrophic and malignant prostatic tissues showed no qualitative difference in isoenzyme patterns although quantitative variations were observed. Malignant tissue contained more isoenzymes with pI values of 4.5-4.8. Patients' sera were found to contain isoenzymes of prostate origin. We have also investigated serum ribonuclease (RNase) activity in patients with prostatic cancer. The serum RNase activity of patients was significantly elevated. No significant correlation was observed between serum acid phosphatase and RNase activity. In some instances, where acid phosphatase activity was in the normal range, RNase activity was elevated. These data suggest that simultaneous measurements of RNase and acid phosphatase activities may be of value in the diagnosis of prostatic cancer. The purified RNase has been isolated from human prostatic tissue and its immunologic properties are being studied.
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PMID:Enzyme markers in human prostatic carcinoma. 6 22

In Anacystis nidulans, upon infection with cyanophage AS-1, after a lag period of 1 h the level of deoxyribonuclease (DNase) activity increaded rapidly up to 15- to 20-fold in 4 to 5 h in the light. In contrast, the ribonuclease and phosphomonoesterase activities increased significantly only 4 to 5 h after infection, i.e. as late as 1 h prior to lysis. In complete darkness, the nuclease levels remained unaltered. However, when the infected cells were exposed to light for 1 or 2 h after infection, the DNase level increased essentially to the same extent in the dark as in continuous light, although the complete replication cycle of the virus was impaired in the dark and cells lysed only in the continuously illuminated cultures. Inhibition of photosystem II with 3-(3,4-dichlorophenyl)-1-dimethylurea during the early illumination period strongly decreased the subsequent, infection-dependent increase in DNase activity in the dark. The virus-induced increase in DNase activity was also inhibited by chloramphenicol. The data suggest that, in spite of the obligate photoautotrophic nature of A. nidulans, dark metabolism is able to support fully the formation of some specific proteins if the triggering of their synthesis takes place in light.
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PMID:Formation in the dark, of virus-induced deoxyribonuclease activity in Anacystis nidulans, an obligate photoautotroph. 17

The activity and sedimentation of acid phosphatase (APase), acid deoxyribonuclease (DNase), and acid ribonuclease (RNase) were investigated throughout growth and encystment in Acanthamoeba castellanii. The activities/mg protein of all 3 hydrolases are high in young cultures and decrease to constant levels in postlog cells. The RNase activity/ameba decreases 50% during growth, whereas the activity/cell of both APase and DNase remains constant. The percent sedimentation at 20,000 g of all 3 enzymes gradually increases from about 40% in midlog to a plateau of 80% in postlog cells. During encystment, the sedimentation behavior of RNase differs from that of APase and DNase. Encystment is characterized by a differential decrease in the activity/cell of the 3 hydrolases, with RNase decreasing most rapidly and APase least rapidly. APase is unique in that a transient increase of its specific activity is noted during encystment, even though its activity/cell is decreasing.
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PMID:Acid hydrolase activity during growth and encystment in Acanthamoeba castellanii. 18 46

The activity of certain enzymes of energy metabolism (cytochrome c oxidase, citrate synthase, malate dehydrogenase, and lactate dehydrogenase) and of lysosomes (beta-glucuronidase, beta-N-acetylglucosamindase, arylsuphatase, ribonuclease, deoxyribonuclease, acid phosphatase, and cathepsin D) was assayed from m. rectus femoris of mice trained 5 days per week, 1 hr per day for 4 weeks according to 4 different programmes: I. running speed 20 m/min, horizontal track, II. 25 m/min, horizontal track, III. 20 m/min 8 degrees uphill inclination, and IV. 25 m/min 8 degrees uphill inclination. Oxidative capacity increased and anaerobic capacity decreased without distinction between the different traning programmes. Of acid hydrolases assayed the activities of beta-glucuronidase and cathepsin D were increased independently of training intensity. Simultaneous histochemical observations on beta-glucuronidase and arylsulphatase activities in the contralateral m. rectus femoris showed more intense staining in red as compared to white muscle fibres. It is suggested that training affected the red fibres and that the applied level of loading was probably too low to cause major involvement of white fibres.
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PMID:Oxidative and lysosomal capacity in skeletal muscle of mice after endurance training of different intensities. 21 99

RNA ligase has been highly purified in good yields from bacteriophage T4-infected Escherichia coli by a rapid and reproducible procedure. The enzyme is free of phosphomonoesterase and ribonuclease activities and is therefore suitable for the synthesis of oligoribonucleotides and for the labeling of the 3'-terminus of RNA. Greater than 90% of the protein in the enzyme preparation migrates as a single band on gradient polyacrylamide gels containing sodium dodecyl sulfate during electrophoresis. For use as a DNA synthesis reagent the enzyme may be reliably freed of deoxyribonuclease activity by an additional chromatographic procedure using a commercially avialable resin.
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PMID:The purification of nuclease-free T4-RNA ligase. 21 95

Studies were undertaken on the turnover of ribosomal RNA and on ribonuclease activity in the liver of the pregnant rat in an attempt to explain the accumulation of liver RNA which occurs during the latter half of pregnancy. Between the 15th and 20th day of gestation the rate constant of degradation, biological half-life and daily rate of synthesis of ribosomal RNA were calculated to be 0.0887, 7.81 days and 6.21 mg per liver per 100g body weight respectively. Corresponding values in non-pregnant rats were 0.123, 5.68 days and 3.47 mg per liver per 100g body weight. The increase in RNA was therefore associated with an increase in its rate of synthesis and a decrease in its rate of breakdown. From the 14th day of pregnancy there was a decrease in alkaline ribonuclease activity and a marked increase in the level of alkaline ribonuclease inhibitor. The activity of acid ribonuclease was found to increase and that of acid phosphatase to decrease during this period.
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PMID:Ribosomal RNA turnover and the level of ribonuclease activity in the liver of the pregnant rat. 23 89

A ribonuclease (ribonucleate 3-pyrimidine-oligonucleotidohydrolase, EC 3.1.4.22) was purified 8300-fold from soluble fraction of beef brain and its properties were investigated. The enzyme is an endonuclease capable of hydrolyzing tRNA, rRNA, poly(C), but shows no activity towards poly(U), poly(A), and poly(G). The preparation is free of deoxyribonuclease, non-specific phosphodiesterase and phosphomonoesterase activity. The enzyme has a pH optimum of 7.6, is not heat stable, has a molecular weight of 25 000, and has a K-m of 134 mu rRNA and K-m of 1600 mug poly(C) per ml.
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PMID:Purification of an alkaline ribonuclease from soluble fraction of beef brain. 23 61

Cytochemical methods are used to examine the distribution and localization of acid phosphatase, non-specific esterase, ribonuclease and peroxidase activity in the walls of the spores of the heterosporous Marsileaceae before and during germination. In the quiescent spore, the principal activity is associated with the perine layer of the wall and the intine, with some activity in the outer, gelatinous wall layer, but none in the exine. The microspores of Marsilea and Pilularia have non-specific esterase activity concentrated in the intine inthe immediate vicinity of the germinal site; that is, above the position of the future male gametangia. The enzymes are not leached from the wall during hydration of the spores, although ribonuclease is redistributed during imbibition with a high concentration of activity remaining in or around the germinal site. The wall enzymes occur together with PAS-reactive and acidic carbohydrates, lipids, and in the microspore perine, beta-lectins. Following the enzyme pattern, the beta-lectins are found to be concentrated in the region of the germinal site. beta-Lectin activity is absent from the megaspore wall. Acidic carbohydrates are confined to the gelatinous wall layer and this layer also binds concanavalin A. In contrast to what has been found for other plant cells, the spore-wall beta-lectins are not water-labile; the activity is not significantly diminished after hydration. This surprising stability suggests that these molecules, together with the enzymes, may be retained in position in the wall by the waterproof overlay of lipid. From the evidence of preliminary developmental studies, it appears that the enzymes associated with the perine layer of the wall originate in the sporophytic tapetal periplasmodium and inclusion of the activity is concurrent with wall differentiation, while the activity associated with the intine is derived from the gametophyte. It is possible, however, in the megaspore at least, that the distribution of the activity may to some extent be influenced by a system of exine channels which communicates between the two domains of the wall during sporogenesis. No definite information is obtained concerning the utility of the enzymes and associated molecules in the life of the spore. Acting separately or in co-operation, their role could conceivably be connected with one or more of four processes; wall differentiation, gametophyte nutrition, gametophyte protection or reproduction. Each of these possibilities is discussed.
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PMID:Developmental mechanisms in heterospory: cytochemical demonstration of spore-wall enzymes associated with beta-lectins, polysaccharides and lipids in water ferns. 52 75

After inducing experimental ileus in albino rats, the authors found changed lysosome enzyme activities in liver homogenizate. In the same kind "free" activity of acid phosphatase and acid ribonuclease is elevated by strangulation ileus. According to literature, these alterations result from changed permeability of lysosome membranes, resp. from rupture of lysosomes. Ileus by obstruction causes no significant changes of the "free" lysosomes activities in liver homogenizate. Increase of acid phosphatase and ribonuclease in blood serum by strangulation or obstruction is equally considerable in both kinds of ileus. The results of these experiments suggest the developing of hepatic damage under both kinds of experimental ileus, the extent of which can be assessed by determination of lysosome enzyme activities.
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PMID:[Changes in the activity of lysosomal enzymes in experimental ileus]. 99 75


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