Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Disulphide-rich proteins of widely differing functions were aligned with the aid of their half-cystinyl residues. This led to the grouping of ribonuclease, phospholipase A, lysozyme, snake venom toxins, bee and scorpion venom peptides, and the plant proteins potatoe carboxypeptidase inhibitor, ragweed pollen allergen, mistletoe toxins and pineapple sulfhydryl protease inhibitor into one super-family of proteins. Very few deletions/insertions were needed to effect alignment and probabilities were calculated for random occurrence of the matches that were found.
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PMID:Homology of functionally diverse proteins. 89 36

Deposition of amyloid beta-protein in senile plaque cores and cerebral vessels is a major neuropathological finding of Alzheimer's disease (AD). Three species of cDNA clones encoding amyloid beta-protein precursors (APP 695, APP 751 and APP 770) were isolated and sequenced. We examined quantitatively the expression of these APP mRNAs in autopsied brains (frontal cortex) of AD patients and control subjects, using Northern blot analysis and the ribonuclease protection assay. Northern blot analysis revealed the production of three types of APP mRNA in the human brain and that AD/control ratios were 2.04 for APP 770 mRNA, 1.11 for APP 751 mRNA and 1.12 for APP 695 mRNA. In the protection assay the ratio of APP 770/APP 751/APP 695 mRNA was approximately 1:10:20 in the brain of control and the AD/control ratios were 2.38, 1.30 and 0.81 for APP 770, APP 751 and APP 695 mRNAs, respectively. These results suggested that an increase in APP 770 and APP 751, harboring a protease inhibitor domain, may disturb the balance between biosynthesis and degradation of APPs, which might lead to amyloid deposition.
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PMID:[Expression of amyloid beta-protein gene in Alzheimer's disease]. 211 40

Expression of three types of mRNA encoding amyloid beta-protein precursor (APP) in various tissues was analysed, using a ribonuclease protection assay, with special reference to Alzheimer's disease (AD). The total content and the proportion of APP mRNAs were specific to each tissue. Among eight tissues examined, the brain was distinct in that the expression level was highest and APP695 mRNA was expressed in abundance. The ratio of APP770/APP751/APP695 mRNAs was approximately 1:10:20 in the cerebral cortex of control brain. The proportions of APP770 mRNA and APP770-plus-APP751 mRNAs increased up to 2.6- and 1.4-fold, respectively, in various regions of AD brain compared with control. The enhanced expression of protease inhibitor-harboring types (APP770 and APP751) may disturb the balance between biosynthesis and degradation of APPs and ultimately lead to accumulation of beta-protein as amyloid.
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PMID:Tissue-specific expression of three types of beta-protein precursor mRNA: enhancement of protease inhibitor-harboring types in Alzheimer's disease brain. 251 87

Recent progresses in DNA technology have made DNA diagnosis possible in clinical laboratories. The diagnosis is characterized by a potential to unveil genetic abnormalities and dispositions in the absence of symptoms, using any tissues not directly affected. Routinization of DNA diagnosis requires nonradioactive probes with sufficient sensitivities for detection and automated systems to use them. These requirements are being met by the latest technology such as polymerase chain reaction (PCR) and time-controlled temperature cyclers. Nonradioactive probes commercially available today, as tested in our laboratory, are not sensitive enough for practical use in single-copy gene analysis, unless combined with PCR. DNA diagnosis is extending to analyses of cDNA or mRNA. Our recent studies using a Northern blot technique and a ribonuclease protection assay indicated that the expression of mRNAs for those amyloid beta-protein precursors that harbor a protease inhibitor increases in the brain of Alzheimer's disease patients.
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PMID:[DNA diagnosis and laboratory tests]. 268 98

The levels of pancreatic digestive enzymes, lysosomal hydrolases, and protease inhibitors were evaluated in ascites fluid from 24 patients with acute pancreatitis diagnosed as alcoholic, gallstone-induced, or idiopathic. In this group the concentrations of amylase (354 +/- 98 ng/ml), immunoreactive cationic trypsinogen (1840 +/- 238 ng/ml), and immunoreactive elastase 2 (1492 +/- 262 ng/ml) were greatly elevated in comparison to the corresponding serum values. Enzyme levels in ascites from the idiopathic pancreatitis group tended to be higher than the levels from the other two groups. Activity of acid phosphatase and beta-glucuronidase was significantly higher in ascites compared to serum in all groups. On the other hand, levels of immunoreactive alpha 1-protease inhibitor and alpha 2-macroglobulin in ascites fluid were about half the average concentrations reported for normal serum. Significant amounts of tryptic amidase activity (61.7 +/- 13.7 micrograms/ml) were observed, indicating a trypsin-alpha 2-macroglobulin complex. These data indicate an imbalance in the protease-to-inhibitor ratio in ascites fluid from patients with acute pancreatitis. Coupled with elevated ribonuclease activity (27.4 +/- 3.4 units), a positive methemalbumin test in 23 of 24 patients (1.1 +/- 0.4 mg hematin/100 ml), and an average protein concentration of 4.0 +/- 0.2 g/100 ml, these observations demonstrate that abdominal paracentesis and the biochemical analyses of ascites fluid provide useful information related to the biochemical events in acute pancreatitis and may be useful in the diagnosis of difficult cases, but their predictive value of severity remains to be established.
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PMID:Biochemical studies in peritoneal fluid from patients with acute pancreatitis. Relationship to etiology. 381 84

Leupeptin, a nontoxic thiol protease inhibitor, has been proposed to have therapeutic use in hereditary muscular dystrophies. The purpose of this study was to characterize the in vivo changes in proteolytic activity of skeletal muscles induced by the repeated administration of leupeptin. Further, whether the modulation of proteolytic capacity by leupeptin affects the repair process of muscle injuries caused by heavy exercise was studied. Leupeptin was administered in mice intraperitoneally at a dose level of 15.5 mg/kg twice a day for 9 days. Leupeptin, known to be an inhibitor of cathepsin B both in vitro and after a single injection in vivo, paradoxically induced an increase of cathepsin B activity in mouse skeletal muscles after repeated administration. In addition, leupeptin administration for 9 days increased the activities of cathepsins C and D, as well as the rate of acid autolysis. The activity of beta-glucuronidase also increased, while those of arylsulfatase, ribonuclease, and alkaline protease were unaffected. No histopathologic changes were observed. At the low dosage used, leupeptin had no effect on the repair process of skeletal muscle after exercise injuries, although several proteolytic processes occur during the regeneration. It is suggested that the increase of acid protease activities in skeletal muscles is an adaptive response to the administration of the proteolytic inhibitor leupeptin and that leupeptin can be administered without prevention or delay of regenerative processes after the onset of myopathic changes.
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PMID:Effects of the protease inhibitor leupeptin on proteolytic activities and regeneration of mouse skeletal muscles after exercise injuries. 638 26

The largest and smallest discrete forms of the estrogen receptor in human breast tumor cytosol were characterized by competitive steroid binding, ultracentrifugation, gel filtration, and electrophoresis in polyacrylamide gels of several concentrations. Incubation of cytosol with [3H]estradiol and centrifugation in glycerol gradients containing 20 mM Na2MoO4 and 0 or 150 mM KCl revealed a 9-10S form of the receptor. It resembles the molybdate-stabilized complexes in cytosols of other human and rodent, malignant and healthy tissues, and the complex detected in breast tumor cytosol containing leupeptin, a bacterial protease inhibitor. Preservation of receptor integrity during purification and discrimination from serum steroid-binding components are facilitated by inclusion of molybdate in all buffers. Possible mechanisms of action of molybdate include the inhibition of ribonuclease action on RNA-associated receptor forms and protection against specific proteolytic cleavage by stabilization of a phosphate group on the vulnerable residue or a neighboring one. During fractionation of tumor cytosol in the absence of molybdate, the receptor is converted to a mixture of fragments. The smallest that retains the bound steroid, the mero-receptor, resembles the products of endogenous and exogenous protease action on receptors for all classes of steroids in a wide range of tissues. The similarities between both the largest and the smallest known forms of the breast tumor estrogen receptor and corresponding forms of other receptors support the notion of the common architecture of steroid receptors in normal and malignant tissues of diverse origins.
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PMID:Human breast tumor estrogen receptor: effects of molybdate and electrophoretic analyses. 747 73