Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of the ribonuclease inhibitor polyvinyl sulfate on the activity of retroviral DNA polymerase and terminal c transferase was examined. This substance was found to be a potent inhibitor of these enzymes by virtue of competition between the sulfated sidechains of the molecule and the template primer for a site on the enzyme. The significance of these findings in relation to searching for reverse transcriptase is discussed.
Cancer Biochem Biophys 1981
PMID:Inhibition of reverse transcriptase by polyvinyl sulfate (PVS). 616 65

Immunochemical techniques with enzymes as the antigen have grown in frequency during the last few years. These techniques have allowed evaluation of enzymes in the presence of endogenous inhibitors. Among those enzymes measured by immunochemical techniques and which have found diagnostic application, mention will be made of alkaline phosphatase (with particular reference to the intestinal, placental, and Regan isoenzymes), lactate dehydrogenase (in which renewed interest has developed due to techniques for specifically measuring the LD-1 isoenzyme), aspartate aminotransferase (of which the cytosolic and mitochondrial forms can now be independently measured by immunochemical techniques), acid phosphatase (for which a specific immunochemical assay for the prostatic enzyme has been widely introduced in diagnostic laboratories), and creatine kinase (for which a variety of immunochemical techniques to measure the M- and B-subunits are now part of standard laboratory assays). Other enzymes which will be discussed in this review include phosphohexose isomerase, amylase, ribonuclease, and lysozyme (muramidase). Finally, the use of enzymes, particularly asparaginase, in the chemotherapy of cancer will be outlined.
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PMID:Immunoassay of enzymes--an overview. 634 26

The activities of serum acid ribonuclease (RNase) were determined in patients with malignant neoplasm or with renal failure. The levels were markedly increased in myelogenous leukemia and renal failure, and only slightly increased in solid cancers, lymphoid malignancies and multiple myeloma. These increases correlated significantly with serum LDH activity in myelogenous leukemia and with creatinine levels in other malignancies or renal failure. The acid RNase content of granulocytes was 22.7-fold higher than that of lymphocytes. The increase of serum acid RNase may suggest an increased granulocyte destruction in myelogenous leukemia and a reduced glomerular filtration in other malignant neoplasms and renal failure.
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PMID:Activities of serum acid ribonuclease in patients with malignant neoplasms or with renal failure. 658 Sep 78

Activity of Poly (C) avid ribonuclease was estimated in sera of 129 patients with different malignancies. All patients had histologically verified carcinomas, normal renal function, and no signs of acute catabolic condition. Activity values were compared with those of normal subjects (U-test, Mann and Whitney) separately for each age decade and type of carcinoma. Patients with ovarian and bronchus carcinoma had statistically elevated activity values throughout all age groups. Colon carcinoma patients showed elevated values in most instances. In patients with pancreatic carcinoma a difference could be detected in only one age group (51-60 years of age). No significant elevation of enzyme activity was detected in carcinoma of the stomach and of the prostate. It is concluded that there are carcinomas leading to elevated ribonuclease activity, although the biological basis of this phenomenon is not understood. No special sensitivity nor specificity of ribonuclease elevation could be demonstrated in pancreatic carcinoma patients. Up to now the usefulness of ribonuclease estimation in prospective carcinoma detection remains questionable.
Cancer 1984 May 01
PMID:Poly (C) avid ribonuclease estimation in patients with solid tumors. A critical evaluation. 670 20

An enzyme complex is a multifunctional catalytic unit that efficiently associates substrates with functionally related enzymes. The enzyme complex provides for the cellular regulation of enzymatic activities by physical interaction of the proteins with each other and by prior alteration of one enzyme's substrate by a related enzyme. Such regulatory abilities may go awry in neoplasia. Components of the protein biosynthetic machinery, such as aminoacyl-tRNA synthetases, have been thought to exist freely in the cytoplasm. However, high-molecular-weight enzyme complexes with aminoacyl-tRNA synthetase activities have been found in mammalian cells. We have been the first to report that the mammalian cell enzymes responsible for modification of tRNA occur in enzyme complexes (molecular weight 900000 daltons) associated with aminoacyl-tRNA synthetases and that the activities of these enzymes differ in normal and leukemic cells. Thus the enzymes responsible for the methylation of tRNA occur in enzyme complexes that provide efficient maturation of tRNA and possible regulation of protein synthesis. In FLC cells a unique enzyme complex composed of tRNA-methyltransferase and aminoacyl-tRNA synthetase activities has also been shown to contain a specific ribonuclease activity and a cysteine-tRNA sulfurtransferase activity. Sulfurtransferase activity has been characterized and optimized for its tRNA and cysteine substrates and mercaptoethanol and cation cofactors. Abnormal activity of this enzyme during neoplasia could result in improper acylation of tRNA and/or infidelity of coding by tRNA. Specific RNase is important in the sizing of percursor tRNA into mature tRNA. Results showed that this sizing was dependent upon the presence of the enzyme complex and the length of the incubation time. Many of the 20 aminoacyl-tRNA synthetases are also found in the complex. Electron microscopy has verified the subunit nature of the complex, seen previously by density gradient centrifugation and gel filtration. Three subunits, each of 300 000 daltons, comprise a complex approximately 200 A in diameter.
Recent Results Cancer Res 1983
PMID:Processing of tRNA is accomplished by a high-molecular-weight enzyme complex. 684 94

Oncofetal markers for colon carcinomas are CSAp, a nonsulfated mucin, a second trimester fetal antigen, an altered thymidine kinase, a monosialoganglioside, and glycolipid antigens. For gastric carcinoma, they are basic fetoprotein, a sulfoglycoprotein, and for pancreatic carcinomas--POA, an oncofetal pancreatic antigen, and designated as CAPI, an oncofetal antigen. Tumor-associated markers for colon carcinomas are: UDP-galactosyltransferase and zinc glycinate marker; for gastric carcinomas, sulfated glycoprotein and for pancreatic carcinomas, pancreas carcinoma-associated antigen, a polycytidylic acid-specific ribonuclease, and galactosyltransferase. Suggested as tumor-specific markers for colon carcinomas are an altered mucoprotein, basic antigen, beta 2-microglobulin-associated antigen, and a specific adenosine deaminase; for gastric carcinomas, a specific protein, an antigen with 3-oxyanthranilic acid, and an antigen of unknown origin in gastric secretions; for pancreatic carcinomas, an antigen with molecular weight of 380,000 daltons and an antigen suggested by tumor immunity.
Cancer Detect Prev 1983
PMID:Gastrointestinal tumor markers, other than carcinoembryonic antigen, and alpha fetal protein. 688 74

Although serum ribonuclease (RNAase) activity (measured by Reddi's method [1]) was significantly higher in 24 patients with pancreatic carcinoma (mean 12.5 units) than in 93 control subjects (mean 5.0 units), 14 patients with chronic pancreatitis (mean 5.2 units) and 83 patients with other primary malignancies (mean 6.8 units), there was much overlap between the four groups and considerable (16.5%) inter-assay variation. Modification of the assay to eliminate a substrate inhibition effect gave acceptable inter-assay variation but abolished any significant difference between the four groups. Changes in serum RNAase activity did not reflect clinical changes in patients with pancreatic carcinoma followed serially during a trial of chemotherapy. The results indicate that serum RNAase is not a useful marker of pancreatic carcinoma.
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PMID:Serum ribonuclease in the diagnosis of pancreatic carcinoma and in monitoring chemotherapy. 713 41

The so-called "plasma" ribonuclease (RNase), described as increased in most patients with pancreatic cancer, was studied in the blood of 92 subjects utilizing the method of Reddi and Holland, to evaluate its reliability in detecting pancreatic tumors. A significant increase of "plasma" RNase was found in pancreatic cancer (p less than 0.01) as compared with controls, non-calcifying chronic pancreatitis (p less than 0.01), calcifying chronic pancreatitis (p less than 0.01), and chronic recurrent pancreatitis (p less than 0.01). Nevertheless increased "plasma" RNase activity was also found in 18/43 patients with chronic pancreatitis, as well as in the majority of the non-pancreatic malignant tumors studied. Furthermore, in 2 out of 22 subjects with pancreatic cancer the enzyme activity was found to be normal. These data suggest that increased "plasma" RNase, although very frequent in pancreatic cancer, is not a marker of pancreatic malignancy.
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PMID:"Plasma"-type ribonuclease in pancreatic cancer diagnosis: a critical appraisal. 734 12

Determinations of plasma ribonuclease were recommended in 1977 by Sheid et al. for laboratory diagnosis of ovarian carcinoma. We investigated the turnover of transfer ribonucleic acid (tRNA) as the substrate of the enzyme in healthy female inbred rats under the multistep-massive dose therapy of ovarian carcinoma usual at the Department of Gynecology, University of Giessen. Whereas mitopodozide, percutaneous irradiation of the abdomen and teniposide did not have any detectable influence on the enzyme activity, the enzyme was strongly suppressed by the other therapy steps: minima of tRNA turnover were observed on the 2nd day with adriamycine, on the 4th day with methotrexate and methotrexate/folinic acid, on the 6th day with cyclophosphamide and fractionated percutaneous irradiation with cyclophosphamide medication in the intervening periods. According to the results, a plasma ribonuclease determination to check the result of therapy should only be performed at an interval of 2 weeks after each therapy step.
J Cancer Res Clin Oncol 1980
PMID:Time-dependent changes of plasma ribonuclease activity in female Wistar rats under combination therapy of ovarian carcinoma. 746 94

The present study gives an evaluation of carcinoembryonic antigen (CEA), macrophage electrophoretic mobility test (MEM), sialyltransferase, galactosyltransferase isoenzyme (SGT), ribonuclease and reverse transcriptase as diagnostic aids in malignant diseases. CEA and sialyltransferase are of certain value in the monitoring of cancer, as their values in the serum may rise before progression of disease or relapse. Both tests are not reliable parameters in the early diagnosis of malignancy. Our results with regard to the MEM test have not proved in any way useful in the diagnosis of cancer. Our preliminary results appear to indicate that, provided further simplification of the method can be achieved, SGT isoenzyme determination seems to be a better means of diagnosing cancer. In view of inherent-methodological difficulties reverse transcriptase has, at present, no clinical application in the diagnosis of cancer.
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PMID:[Developments in the serological diagnosis of malignant diseases]. 746 58


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