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:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The properties of enzyme activities hydrolysing the sulphate esters of dehydroepiandrosterone, oestrone and p-nitrophenol are reported. The preparation studied was obtained from the microsomal fraction of human placenta by ultrasonic treatment and addition of Triton X-100. 2. The behaviour of the preparation during sedimentation at 105000g and attempts at purification indicated that the activities were particulate. Electron microscopy demonstrated the rupture of vesicular structures approx. 0.5mu in diameter concurrent with the release of activity. 3. The three activities were always associated throughout repeated attempts at separation by sucrose-density-gradient centrifugation and Sephadex-gel filtration. On the basis of kinetic studies, stability studies and treatment with butanol and ribonuclease it was concluded that a separate enzyme is responsible for each of the three activities. Widely varying plots of activity as a function of pH were consistent with this conclusion. 4. On the basis of sensitivity of the enzymes hydrolysing dehydroepiandrosterone sulphate and oestrone sulphate to ribonuclease and sensitivity of all three enzymes to lipase, it was concluded that the three enzymes are bound to a particle containing lipid and RNA. Enzymic activity is dependent on structural integrity of the particle. 5. A spectrophotometric method for the assay of oestrone sulphate hydrolysis is described. 6. Hydrolysis of nitrocatechol sulphate by human placenta under conditions described for arylsulphatases A and B is reported.
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PMID:Properties of steroid sulphatase and arylsulphatase activities of human placenta. 606 Apr 47

Because of the location of the pancreas deep in the abdominal cavity, laboratory tests play a major role in the diagnosis of pancreatic diseases. Amylase and lipase determinations in serum are most frequently performed and they complement each other. However, false positive and false negative results are observed. In order to increase the sensitivity and specificity of diagnostic tests, urine amylase determinations, measurements of the CAmyl Ccreat ratio and amylase isoenzyme determinations are performed. The benefits of these procedures and their limitations will be discussed. The increased sensitivity and specificity of immunoreactive trypsin determinations and contributions of this test to the early diagnosis of pancreatic disease will be described. This test seems to have some usefulness in the early diagnosis of cancer, together with the secretin and pancreozymine-cholecystokinin test and the test for ribonuclease activity in serum.
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PMID:Enzyme measurements in the investigation of pancreatic diseases. 616 Aug 3

The transplantable pancreatic acinar carcinomas of rat established recently provide useful model systems to examine the composition of secretory proteins as well as the secretory process in transformed pancreatic exocrine epithelium. The neoplastic acinar cells exhibit considerable variation in the extent of cytodifferentiation. In the present study the enzymatic profile of this heterogeneous tumor cell population has been investigated by the indirect immunofluorescent technique using antibodies against six pancreatic enzymes. By immunofluorescence, all neoplastic cells stained positively for the six enzymes tested: amylase, lipase, carboxypeptidase A, chymotrypsinogen, trypsinogen, and ribonuclease. Some variability in the intensity of immunofluorescence was noted, suggesting possible quantitative differences in the content of a given enzyme among tumor cells. These observations suggest that neoplastic acinar cells with or without secretory granules contain secretory proteins, but to a variable extent.
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PMID:Immunohistochemical localization of pancreatic exocrine enzymes in normal and neoplastic pancreatic acinar epithelium of rat. 616 57

Rats were fed a protein-rich or carbohydrate-rich diet for 3 weeks. By means of a double-label technique, we compared the protein-synthesizing patterns under these conditions. After 3 weeks of feeding, the relative rates of all the identified secretory enzymes and of some unidentified components had changed. The synthetic rates of the proteolytic proenzymes and of ribonuclease were increased after feeding a protein-rich diet, whereas those of the amylases and of lipase were lowered. The protein synthetic patterns of the rat pancreas under two extreme feeding conditions were compared to that of the pancreas of rats constantly fed a balanced diet of an intermediate composition. The results indicated that changes in relative rate of synthesis are mainly provoked by the protein-rich diet. Only the synthetic rate of the anodic chymotrypsinogen was strongly influenced by the carbohydrate-rich diet.
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PMID:Effect of feeding diets of different composition on the protein synthetic pattern of the rat pancreas. 616 99

We have examined the secretogogue responsiveness and the pattern of secretory proteins produced by a transplantable rat pancreatic acinar cell tumor. Dispersed tumor cells were found to discharge secretory proteins in vitro when incubated with hormones that act on four different classes of receptors: carbamylcholine, caerulein, secretin-vasoactive intestinal peptide, and bombesin. With all hormones tested, maximal discharge from tumor cells was only about one-half that of control pancreatic lobules, but occurred at the same dose optima except for secretin, whose dose optimum was 10-fold higher. Biochemical analysis of secretory proteins discharged by the tumor cells was carried out by crossed immunoelectrophoresis and by two-dimensional isoelectric focusing-SDS polyacrylamide gel electrophoresis. To establish a baseline for comparison, secretory proteins from normal rat pancreas were identified according to enzymatic activity and correlated with migration position on two-dimensional gels. Our results indicate that a group of basic polypeptides including proelastase, basic trypsinogen, basic chymotrypsinogen, and ribonuclease, two out of three forms of procarboxypeptidase B, and the major lipase species were greatly reduced or absent in tumor cell secretion. In contrast, the amount of acidic chymotrypsinogen was notably increased compared with normal acinar cells. Although the acinar tumor cells are highly differentiated cytologically and express functional receptors for several classes of pancreatic secretagogues, they show quantitative and qualitative differences when compared with normal pancreas with regard to their production of secretory proteins.
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PMID:Biochemical analysis of secretory proteins synthesized by normal rat pancreas and by pancreatic acinar tumor cells. 618 2

We have previously established that secretory proteins from a rat acinar cell tumor lack two forms of procarboxypeptidase B, are deficient in a major lipase species, and possess markedly reduced amounts of the basic proteins proelastase, basic chymotrypsinogen, basic trypsinogen and ribonuclease (Iwanij, V., and J.D. Jamieson, J. Cell Biol., 95:734-741). Because secretory proteins are markers for acinar cell differentiation, we sought to establish whether the secretory protein profile of the acinar cell tumor is unique to the transformed cell or whether it resembles that of a stage of normal pancreatic development. To this end, we compared the secretory protein pattern from acinar tumor cells with that of rat pancreatic rudiments at days 19-22 of gestation and through day 21 of the postnatal period. Two-dimensional IEF-SDS gel electrophoresis coupled with biosynthetic labeling and fluorography indicates a time-dependent appearance of individual secretory proteins with basic polypeptides, except for amylase, appearing in the terminal stages of differentiation. In comparison, the secretory protein pattern of the acinar tumor cells most closely resembles that of day-19 embryonic pancreatic rudiments. We propose that the cells of the acinar cell tumor may, in part, mirror a stage of normal pancreatic development.
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PMID:Comparison of secretory protein profiles in developing rat pancreatic rudiments and rat acinar tumor cells. 618 3

Protein synthesis and secretion during in vitro pancreatic development and after treatment with the glucocorticoid dexamethasone and the thymidine analog 5-bromodeoxyuridine (BrdU) was monitored using two-dimensional gel electrophoresis. At 14 days gestation, the synthesis of more than 200 proteins and the secretion of a complex set of proteins was detected. The relative rate of synthesis and secretion of the majority of this set of proteins decreased dramatically during development; after 6 days of culture most were no longer detected. In contrast, the synthesis and secretion of pancreas-specific exocrine proteins amylase, a Sepharose binding protein (protein 2), and chymotrypsinogen first detected after one day in culture, increased throughout the 6-day culture period. Other pancreatic digestive (pro)enzymes normally found in the adult such as the basic form of chymotrypsinogen, lipase, ribonuclease, and trypsinogen were not detected during the culture period. Thus at least two distinct regulatory events are involved in the expression of the exocrine genes during development. Dexamethasone treatment during the 6-day culture period selectively increased the synthesis of amylase and several other minor secretory proteins. BrdU treatment caused major changes in the protein synthetic and secretory patterns of the pancreas as well as in morphogenesis. BrdU treated pancreases showed greatly reduced synthesis of amylase, protein 2, and chymotrypsinogen and prolonged synthesis of many proteins normally detected only at early stages of pancreatic development. BrdU treatment also stimulated the secretion of a set of proteins ostensibly associated with duct cells. Thus, BrdU specifically alters the developmental program of the pancreas.
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PMID:Effects of dexamethasone and 5-bromodeoxyuridine on protein synthesis and secretion during in vitro pancreatic development. 619 25

24-h intravenous caerulein infusion studies in the rat were combined with in vitro amino acid incorporation studies followed by high-resolution separation of proteins by two-dimensional isoelectric focusing and SDS gel electrophoresis to study the extent to which persistent changes in the biosynthesis of exocrine pancreatic proteins are regulated by cholecystokinin-like peptides. Beginning in the third hour of optimal hormone infusion at 0.25 microgram kg-1 h-1, changes were observed in the synthetic rates of 12 proteins, which progressed over the course of the 24-h study. Based on coordinate response patterns, exocrine proteins could be classified into four distinct groups. Group I (trypsinogen forms 1 and 2) showed progressive increases in synthetic rates reaching a combined 4.3-fold increase over control levels. Group II (amylase forms 1 and 2) showed progressive decreases in synthesis to levels 7.1- and 14.3-fold lower than control levels, respectively. Group III proteins (ribonuclease, chymotrypsinogen forms 1 and 2, procarboxypeptidase forms A and B, and proelastase 1) showed moderate increases in synthesis, 1.4-2.8-fold, and group IV proteins (trypsinogen 3, lipase, proelastase 2, and unidentified proteins 1-4) did not show changes in synthesis with hormone stimulation. Regulation of protein synthesis in response to caerulein infusion was specific for individual isoenzymic forms in the case of both trypsinogen and proelastase. The ratio of biosynthetic rates of trypsinogen forms 1 + 2 to amylase forms 1 + 2 increased from a control value of 0.56 to 24.4 after 24 h of hormonal stimulation (43.5-fold increase). Biosynthetic rates for an unidentified protein (P23) with an Mr = 23,000 and isoelectric point of 6.2 increased 14.2-fold, and the ratio of synthesis of P23 to amylase 2 increased 200-fold during caerulein infusion. During hormone stimulation the anticoordinate response in the synthesis of pancreatic glycosidases (decreased synthesis) and serine protease zymogens (increased synthesis) explain previous observations that showed little change in rates of total protein synthesis under similar conditions.
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PMID:Hormonal stimulation in the exocrine pancreas results in coordinate and anticoordinate regulation of protein synthesis. 620 98

Porcine rotaviral infectivity for continuous porcine kidney (PK-15) cells was enhanced by incorporation of pancreatic endopeptidases into the cell culture maintenance medium. Marked enhancement of infectivity was induced by trypsin, whereas elestase and alpha-chymotrypsin enhanced infectivity to a lesser extent. Bacterial protease also induced some enhancement of porcine rotaviral infectivity. A synergistic enhancement of porcine rotaviral infectivity was noticed with trypsin and alpha-chymotrypsin combined. Porcine rotaviral infectivity was not affected by incorporation of alpha-amylase, alkaline phosphatase, beta-galactosidase, carboxypeptidase-A, deoxyribonuclease, enterokinase, lipase, or ribonuclease into the maintenance medium.
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PMID:Porcine rotaviral infection of cell culture: effects of certain enzymes. 624 64

All strains of Legionella pneumophila tested produced detectable levels of extracellular protease, phosphatase, lipase, deoxyribonuclease, ribonuclease, and beta-lactamase activity. Weak starch hydrolysis was also demonstrated for all strains. Elastase, collagenase, phospholipase C, hyaluronidase, chondroitinase, neuraminidase, or coagulase were not detected in any of these laboratory-maintained strains.
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PMID:Extracellular enzymes of Legionella pneumophila. 626 49


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