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 action of beryllium on the following enzymes has been examined: alkaline phosphatase (Escherichia coli and kidney), acid phosphatase, phosphoprotein phosphatase, apyrase (potato), adenosine triphosphatase (liver nuclei, liver mitochondria, brain microsomes), glucose 6-phosphatase, polysaccharide phosphorylases a and b, phosphoglucomutase, hexokinase, phosphoglyceromutase, ribonuclease, A-esterase (rabbit serum), cholinesterase (horse serum), chymotrypsin. Alkaline phosphatase and phosphoglucomutase are inhibited by 1mum-beryllium sulphate whereas the other enzymes are largely unaffected by 1mm-beryllium sulphate. 2. Possible mechanisms for the inhibition of phosphoglucomutase and alkaline phosphatase are discussed.
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PMID:The inhibition of enzymes by beryllium. 428 87

The complementary strands of reovirus double-stranded ribonucleic acid (ds RNA) are synthesized sequentially in vivo and in vitro. In both cases, preformed plus strands serve as templates for the synthesis of the complementary minus strands. The in vitro synthesis of dsRNA is catalyzed by a large particulate fraction from reovirus-infected cells. Treatment of this fraction with chymotrypsin or with detergents which solubilize cellular membranes does not alter its capacity to synthesize dsRNA. The enzyme or enzymes responsible for dsRNA synthesis remain sedimentable at 10,000 x g after these enzyme or detergent treatments, indicating their particulate nature. Pretreatment of this fraction with ribonuclease, however, abolishes its ability to catalyze dsRNA synthesis, emphasizing the single-stranded nature of the template and its location in a structure permeable to ribonuclease. In contrast, the newly formed dsRNA is resistant to ribonuclease digestion at low salt concentrations and hence is thought to reside within a ribonuclease-impermeable structure.
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PMID:Mechanism of reovirus double-stranded ribonucleic acid synthesis in vivo and in vitro. 516 74

On the basis of earlier energy computations, the various single peptide units in proteins were designated as helix-making or helix-breaking.(1) With the use of these designations, empirical rules for distinguishing between alpha-helical and non-alpha-helical regions of proteins have been formulated. These rules include conditions for initiation and termination of a helical segment which, when combined with changes in the designation of three peptide units, correctly identify the helical or nonhelical character of over three fourths of the individual peptide units in four proteins of known amino acid sequence and structure: myoglobin, lysozyme, tosyl-alpha-chymotrypsin, and ribonuclease-A. The model is discussed, some of its predictions are checked, and further predictions about the structure of various proteins are made.
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PMID:The influence of short-range interactions on protein onformation. II. A model for predicting the alpha-helical regions of proteins. 525 50

It is shown that alpha-helical content of eleven proteins is well correlated with alanine plus leucine content. These residues, taken singly or together, are to a first approximation randomly distributed in the four proteins whose tertiary structures have been determined (i.e., myoglobin, lysozyme, ribonuclease, alpha-chymotrypsin). A model based on the concept that certain randomly distributed residues specifically participate in helix nucleation is shown to be in reasonable agreement with the presently published structures.
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PMID:A model of alpha-helical distribution in proteins. 569 10

This paper reports the isolation and characterization of a soluble antigen shared by the liver and kidney of human and some other animal species. Homogenates of human liver in saline were centrifugated at 27,000 g and the supernatants were fractionated by preparative polyacrylamide gel electrophoresis. The gels were divided in sections and each was injected into rabbits; after absorption with polymerized normal human serum, the antiserum obtained by injecting one of the sections reacted only with saline extracts of human liver and kidney when tested against a variety of human tissue extracts. The absorbed antiserum, polymerized and insolubilized with glutaraldehyde, was used to purify the antigen by affinity chromatography. The purified antigen proved to be a glycoprotein containing 19 percent carbohydrate, had a molecular weight of 5.8-6.0 x 10(4) Daltons and a pI of 7.2-7.4. The antigen, relatively thermostable, was precipitated by 35-55 percent ammonium sulphate; its antigenic activity was not affected by extraction with 0.6 N perchloric acid or by incubation with ribonuclease, deoxyribonuclease or neuraminidase but was destroyed by incubation with ttypsin or chymotrypsin. Immunoperoxidase studies showed that the antigen appeared concentrated in the neclei of liver and kidney glomerular epithelial and tubular epithelial cells in humans and rats. The antigen could not be detected in human hepatomas or hypernephromas or in the rat Morris hepatoma 5123.
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PMID:Isolation and characterization of a human liver and kidney-specific protein: the hepato-renal (H-R) antigen. 615 31

Pancreatic amylase, elastase 1, elastase 2, cationic trypsin, chymotrypsin, ribonuclease (RNase), phospholipase A2, gamma-glutamyl transpeptidase (gamma-GTP) and pancreatic secretory trypsin inhibitor (PSTI) were purified and characterized from human pancreatic juice and pancreatic tissue. During the purification of these enzymes, two enzymes previously not reported were found. A pancreatic deamidase and a renal endopeptidase were purified and characterized. Specific and reliable radioimmunoassays (RIAs) were developed for all pancreatic enzymes and inhibitor. The purpose of immunoassay for pancreatic enzymes and inhibitor was discussed, and clinical application for the diagnosis of pancreatic diseases was demonstrated. Messenger RNA (mRNA) of amylase was isolated from human pancreas and parotid gland, and used to prepare a complementary DNA (cDNA). The nucleotide sequence and the predicted amino acid sequence of these clones were now being determined. The application of the present investigation to elucidation of pathogenesis of pancreatic enzyme-producing diseases was discussed.
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PMID:[Purification and development of immunoassay of pancreatic enzymes and trypsin inhibitor, and their application to elucidation of pathogenesis of various pancreatic and pancreatic enzyme-producing diseases]. 620 25

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

'A' particle of Coxsackievirus B3 were generated from native virus by heating and purified by sucrose gradient centrifugation. These particles were found to be similar to 'A' particles formed by elution from cellular receptors of HeLa cells. Electrophoretic analysis of [35S]methionine-labelled 'A' particles revealed that treatment of the particles with chymotrypsin resulted in the cleavage of VP1 and the formation of a cleavage product which migrated between VP2 and VP3. Analysis of the protease-treated material on sucrose gradients revealed a ribonuclease-sensitive particle which sedimented more slowly than an 'A' particle. This particle apparently degraded to release the viral RNA, thereby providing an in vitro model for protease-mediated uncoating of 'A' particles. The subviral particles of Coxsackievirus B3 were found to be immunoprecipitable with heterotypic Coxsackievirus group B antisera, thereby providing a method for the recovery of products produced in the cell early in infection. Infected cells which had been treated to remove unreacted virus were disrupted, an the lysates were reacted with heterotypic antisera. Analysis of the precipitated material revealed that no cleavage products were formed and no polypeptides were lost. Therefore, it appears that proteolysis is not involved in the uncoating of Coxsackievirus B3 in infected cells.
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PMID:Proteolytic cleavage of VP1 in 'A' particles of coxsackievirus B3 does not appear to mediate virus uncoating by HeLa cells. 627 Feb 73

Using the method of isomer-specific proteolysis (ISP), the cis-trans nature of the peptide bonds involving prolines-114 and -117 in ribonuclease (RNase) has been investigated. These studies involve the pretreatment of RNase first with either a short pepsin pulse or a short mercaptoethanol pulse to irreversibly unfold the protein and then with a short chymotrypsin pulse to quickly cleave the Tyr115-Val116 bond so that the chain is suitably trimmed for the subsequent stereospecific cleavage either by aminopeptidase P, to investigate proline-117, or by a proline-specific endopeptidase, to investigate proline-114. The most reasonable interpretation of our results suggests that proline-117 is essentially 100% trans in both the native and unfolded states, so it apparently makes no direct contribution to the slow refolding kinetics of RNase. It is also determined that proline-114 is 100% cis in native RNase and ca. 95% cis in reversibly unfolded RNase so only 5% of the unfolded RNase can be rate limited by trans to cis isomerization of proline-114 during refolding. Careful spectroscopic studies of refolding show that the smallest and slowest of the refolding phases, the ct phase, has the proper amplitude (5%), relaxation time (400 s at 10 degrees C), and activation energy (17 kcal) for a phase that is rate limited by the trans to cis isomerization of proline-114. Measurements of the kinetics of binding of cytidine 2'-monophosphate during refolding further show that RNase does not become active until proline-114 has isomerized to the native cis configuration. It is concluded that none of the three prolines thus far examined (i.e., prolines-93, -114, and -117) by the ISP method is involved in the formation of a fully active, nativelike intermediate which has "incorrect" proline isomers. The specific structural process which is responsible for the largest of the three slow refolding phases, the XY phase, is still undetermined. Although ISP results on proline-42 are not yet available, it seems possible that this slow phase may be rate limited by a process other than proline isomerization. In unrelated studies, results from chymotrypsin hydrolyses of several short peptides containing the sequence -X-Y-Pro- show that cleavage of an active X-Y bond is very slow when it is immediately adjacent on the amino side of a proline peptide bond. Thus, chymotrypsin cleavage may not be generally useful as the analytical step in isomer-specific proteolysis.
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PMID:Involvement of prolines-114 and -117 in the slow refolding phase of ribonuclease A as determined by isomer-specific proteolysis. 644 92

In a study of factors that influence the remaining secondary structure of reduced chicken eggwhite lysozyme, N-acetyl-D-glucosamine (NAG) and N,N'-diacetylchitobiose (di-NAG) were found to alter the circular dichroic (CD) spectrum of the reduced protein and its carboxymethyl derivative (Cml). Thus, negative ellipticities in the far u.v. were greater in the presence of the analogs, with NAG being the more effective. For Cml, curve fitting analysis of the CD data indicated an increased helical content in the presence of NAG by an average of 3% of the chain length, while beta-structure decreased by an equivalent amount. Other compounds structurally related to NAG produced no similar effects on the CD spectrum of Cml, nor were comparable effects of NAG in evidence on the Cm reduced derivatives of ribonuclease, chymotrypsin, wheat germ agglutinin, or alpha-lactalbumin. The effect therefore appears specific between NAG and Cml. Conversion of the tryptophan residue at Position 62 of Cml to the oxindolealanyl derivative prevented these effects of NAG, and this residue may therefore participate in the interaction. During a 4-day incubation at room temperature, the analog preserved the CD spectrum of Cml as well as its concentration. This effect was nearly specific when compared with other Cm reduced proteins and with other carbohydrates. Only one, N-acetyl mannosamine, was effective in preserving the concentration of Cml, but not the CD spectrum. Since D-glucosamine was entirely without effect on either the CD spectrum of Cml or on its change during incubation, the acetyl group appears essential for the NAG-Cml interaction. The specificity between NAG and Cml is tentatively accounted for in terms of interactions with the primary structure, rather than with the remaining secondary structure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evidence for interaction of substrate analogs with chicken eggwhite lysozyme after exhaustive reduction of disulfide bonds. 651 17


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