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)

A soluble ribonuclease inhibitor from the human placenta has been purified 4000-fold by a combination of ion exchange and affinity chromatography. The inhibitor has been isolated in 45% yield (about 2 mg/placenta) as a protein that is homogeneous by sodium dodecyl sulfate-gel electrophoresis. In common with the inhibitors of pancreatic ribonuclease from other tissues that have been studied earlier, the placental inhibitor is an acidic protein of molecular weight near 50,000; it forms a 1:1 complex with bovine pancreatic RNase A and is a noncompetitive inhibitor of the pancreatic enzyme, with a Ki of 3 X 10(-10) M. The amino acid composition of the protein has been determined. The protein contains 30 half-cystine plus cysteine residues determined as cysteic acid after performic acid oxidation. At pH 8.6 the nondenatured protein alkylated with iodoacetic acid in the presence of free thiol has 8 free sulfhydryl groups. The inhibitor is irreversibly inactivated by sulfhydryl reagents and also by removal of free thiol from solutions of the protein. Inactivation by sulfhydryl reagents causes the dissociation of the RNase - inhibitor complex into active RNase and inactive inhibitor.
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PMID:Ribonuclease inhibitor from human placenta. Purification and properties. 56 Mar 77

The dissociation of cervical cell suspensions after various chemical and enzymatic treatments was monitored by using the Centrifugal Cytology rotor to produce glutaraldehyde-fixed dispersions on conventional microscope slides and subsequent Pap staining. A special program was written in RPG II to record and analyze the results of the dissociation experiments in terms of white blood cells and the true cervical cells ("other cells"), and the degree of dissociation and recovery of both classes of cells. Since accurate differential counts on the untreated Ayre scrapes were difficult, the samples were syringed gently to break up the large or adventitious clumps. Cumulated results from control preparations indicate that the white blood cells and "other cells" are composed respectively of 92 and 63% single cells. The cells were further dissociated by: dissolving the cervical mucin sequentially with dithiothreitol and iodoacetic acid; depolymerizing the nucleohistone gel with ribonuclease; solubilizing the desmosomes with EDTA; removing the remaining cellular agglutinins with Varidase; and finally mechanical dispersion by hypertonic shock. The optimum procedure for dissociation involves the use of ribonuclease, dithiothreitol, iodoacetic acid EDTA, Varidase and sucrose shock. The white blood cells are now monodisperse and 81% of the "other cells" are found as single cells. If nuclear separation by two diameters is considered sufficient 98% of the "other cells" are single. The slide preparations are now sufficiently good that a scanning system is feasible.
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PMID:A procedure for dissociating Ayre scrape samples. 89 1

The major ribonuclease of human liver has been isolated in a four-step procedure. The protein appears homogeneous by several criteria. The amino acid composition and the amino-terminal sequence of the enzyme indicate that the protein is related to human pancreatic ribonuclease and to angiogenin, and that it may be identical with an eosinophil-derived neurotoxin and to a ribonuclease that has been isolated from urine. The catalytic activity of the liver ribonuclease and its sensitivity to iodoacetic acid inactivation also relate the enzyme to the pancreatic RNases, but the liver protein is clearly differentiated by immunological measurements. Antibodies to the liver ribonuclease inhibit its activity, but not that of the human pancreatic enzyme; cross-reactivity in a radioimmunological assay is small but measurable. Immunochemical measurements have been used to examine the distribution of the liver-type protein in other tissues. Inhibition of enzyme activity by anti-liver ribonuclease shows that a cross-reactive enzyme is predominant in extracts of spleen and is a significant component in kidney preparations, while the liver-type protein is almost absent in brain or pancreas homogenates. Cross-reactive ribonuclease is present in serum, but levels are not correlated with any of the disease states examined.
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PMID:Purification and characterization of a ribonuclease from human liver. 318 86

A base non-specific and adenylic acid preferential ribonuclease from Aspergillus saitoi (RNase M) was modified by [14C]iodoacetic acid. RNase M was inactivated with concomitant incorporation of about 1 mol equivalent of carboxymethyl group. Carboxymethylated RNase M (CM RNase M) thus obtained was reduced and carboxymethylated (RCM CM RNase M). From tryptic and chymotryptic digests of RCM CM RNase M, two carboxymethylated histidine-containing peptides labeled with radioactivity were isolated. The amino acid sequences of these two peptides were determined to be Thr-Ile-His-Gly-Leu-Trp-Pro-Asp-Asn-Cys-Asp-Gly-Ser-Tyr... and His-Gly-Thr-Cys-Ile-Asn-Thr-Ile-Asp-Pro-Ser-Cys-Tyr-Pro-Asp-Asp-Tyr-Ala. .... The distribution of the radioactivity on the former and latter peptides was 43% and 57%, respectively. The results indicated that two histidine residues are involved in the active site of RNase M, and the modification of either one of the two histidine residues inactivates RNase M. The CD spectrum of carboxymethylated RNase M indicated that some tryptophan residue(s) with a CD band at 287 nm is in the proximity of the active site histidine residues of RNase M.
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PMID:Site of alkylation of the major ribonuclease from Aspergillus saitoi with iodoacetate. 371 Oct 38

1. Bison ribonuclease was isolated from pancreas glands of Bison bison by acid extraction, (NH(4))(2)SO(4) fractionation, affinity chromatography on Sepharose-5'-(4-aminophenylphosphoryl)uridine 2',3'-phosphate and ion-exchange chromatography on Bio-Rex-70. 2. The selectivity of the affinity column towards bison ribonuclease in heterogeneous protein solutions was greatly improved by employing piperazine buffers at pH5.3, which decreased non-specific interactions of other proteins. Rapid desorption from the affinity column was obtained with sodium phosphate buffer (pH3). 3. Bison ribonuclease has a total amino acid content very similar to ox ribonuclease. Inactivation of bison ribonuclease with iodoacetic acid leads to the formation of 0.62 residues of pi-carboxymethylhistidine and 0.36 residues of tau-carboxymethylhistidine. The amino acid composition of peptides isolated from diagonal peptide ;maps' and also of peptides isolated after pH1.6 and 2.4 two-dimensional high-voltage electrophoresis of a digest of bison ribonuclease labelled with pyridoxal 5-phosphate indicates that there is complete homology between ox and bison ribonucleases. 4. The Schiff-base attachment site of pyridoxal 5-phosphate was identified as lysine-41 by NaBH(4) reduction followed by peptide isolation.
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PMID:The isolation and partial characterization of ribonuclease A from Bison bison. 477 70

A ribonuclease (RNase) has been isolated from normal human pancreas obtained upon autopsy. About 5 mg of RNase is normally recovered per kilogram of pancreas, equivalent to ca. 70% of the total activity and a 700-fold purification from the initial acidified extract. The specific activity of the purified enzyme is identical with that of bovine pancreatic ribonuclease, and a single component is found in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and reversed-phase high-pressure liquid chromatography. Aggregation of the protein is found upon ultracentrifugation under native and denaturing conditions, and several bands of equal specific activity are seen in polyacrylamide gel electrophoresis of the native protein. At least two components are glycoproteins. A molecular weight of 15 000 is estimated from sodium dodecyl sulfate gel electrophoresis, gel filtration, and amino acid and peptide analyses. The enzyme is related to bovine pancreatic RNase, but distinguishable by amino acid analysis, tryptic peptide maps, and low cross-reactivity of antibodies with the heterologous enzymes. The human enzyme is also inactivated by treatment with iodoacetic acid at pH 5.5 and is essentially identical with bovine RNase in its far-ultraviolet circular dichroism spectrum. The human RNase is like bovine pancreatic RNase catalytically; RNA is cleaved at pyrimidine residues, and activity against poly(cytidylic acid) is high.
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PMID:Purification and characterization of human pancreatic ribonuclease. 678 51

Purkinje cell toxicity is one of the characteristic features of the Gordon phenomenon, a syndrome manifested by ataxia, muscular rigidity, paralysis, and tremor that may lead to death (Gordon, 1933). Two members of the RNase superfamily found in humans, EDN (eosinophil-derived neurotoxin) and ECP (eosinophil cationic protein), cause the Gordon phenomenon when injected intraventricularly into guinea pigs or rabbits. We have found that another member of the RNase superfamily, an antitumor protein called onconase, isolated from Rana pipiens oocytes and early embryos, will also cause the Gordon phenomenon when injected into the cerebrospinal fluid of guinea pigs at a dose similar to that of EDN (LD50, 3-4 micrograms). Neurologic abnormalities of onconase-treated animals were indistinguishable from those of EDN-treated animals, and histology showed dramatic Purkinje cell loss in the brains of onconase-treated animals. The neurotoxic activity of onconase correlates with ribonuclease activity. Onconase modified by iodoacetic acid to eliminate 70% and 98% of the ribonuclease activity of the native enzyme displays a similar decrease in ability to cause the Gordon phenomenon. In contrast, the homologous bovine pancreatic RNase A injected intraventricularly at a dose 5000 times greater than the LD50 dose of EDN or onconase is not toxic and does not cause the Gordon phenomenon. A comparison of the RNase activities of EDN, onconase, and bovine pancreatic RNase A using three pancreatic RNA substrates demonstrates that onconase is orders of magnitude less active enzymatically than EDN and RNase A. Thus, another member of the RNase superfamily in addition to EDN and ECP can cause the Gordon phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Toxicity of an antitumor ribonuclease to Purkinje neurons. 830 53

Pancreatic cancer is the most deadly gastrointestinal malignancy because of its propensity for local invasion and early metastasis. Integrin chains, in particular beta4, can promote invasion in other cancers. The effect of sodium butyrate (NaBT), which induces differentiation in transformed cells, on integrin expression is unknown. The purpose of this study was to determine patterns of integrin expression in pancreatic cancer cells and investigate the effect of NaBT on integrin expression and invasion. Integrin expression was assessed in the less invasive MIA-PaCa-2 and PANC-1 and more invasive L3.6, AsPC-1, and SUIT-2 human pancreatic cancer cell lines by ribonuclease (RNase) protection assay. Western blotting and immunofluorescent staining for beta4 expression was determined after NaBT treatment. Matrigel invasion chambers were used to assess pancreatic cancer cell invasion. beta4 and beta7 integrin expression was highest in L3.6, AsPC-1, and SUIT-2 cells. NaBT reduced the expression of beta4 integrin in AsPC-1 cells including less cell surface beta4. Invasion of AsPC-1 cells was also reduced by NaBT. Expression of beta4 is higher in more aggressive pancreatic cancer cells; NaBT inhibits beta4 expression and invasion. NaBT may represent a novel strategy to inhibit pancreatic cancer invasion and improve the prognosis of this deadly disease.
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PMID:Butyrate inhibits pancreatic cancer invasion. 1459 59