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 binding isotherms of native bovine serum albumin with cationic detergents, such as octyl, decyl, dodecyl and tetradecylpyridinium bromides were determined at pH 6.8 and 3.4 at 25 degrees C. The isotherms for dodecyl and tetradecylpyridinium bromides were also determined at 3 degrees C. The average number of detergent cations bound increased with increasing hydrocarbon chain length. At low detergent concentration the binding of all alkylpyridinium bromides was smaller at pH 3.4 than at pH 6.8. Dodecylpyridinium bromide was bound to native beta-lactoglobulin, aldolase, ovalbumin, haemoglobin, myoglobin, lysozyme, trypsin and ribonuclease at pH 6.8. No binding occurred to alpha-chymotrypsin and chymotrypsinogen. The free enthalpy change, --delta G degrees, calculated from intrinsic association constants K was determined.
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PMID:Protein-cationic detergent interaction. Equilibrium dialysis study of the interaction of bovine serum albumin and other proteins with alkylpyridinium bromide. 49 43

Adenylate cyclase from purified beef thyroid membranes has been solubilized by the use of Triton N-101 after preactivation with guanosine 5'-(beta, gamma-imido)-triphosphate. The soluble activity passed a 0.22- micron filter, was not sedimented at 100,000 X g for 2 h, and behaved like aldolase in sucrose density gradients and on Sepharose 6B. From comparison of the sedimentation in D2O and H2O the partial specific volume was found to be like that of globular proteins (0.75 +/- 0.006), hence little detergent appeared to be bound to the enzyme. The sedimentation coefficient was 7.4 +/- 0.15, the Stokes radius 45 A, and the molecular weight 159,000. Prestimulation by thyrotropin did not survive solubilization. The stimulation produced by guanosine 5'-(beta, gamma-imido)triphosphate persisted as did the more active state resulting from pretreatment with both this nucleotide plus thyrotropin. Thyrotropin did not stimulate the solubilized enzyme. The Km for ATP, thermal stability, and inhibition by Ca2+ were identical for the membrane-bound and soluble enzyme, while the pH optimum was increased 0.5 unit in the latter. Polyanions and phenothiazines inhibited both preparations equally, whereas only membranes responded to stimulation by polylysine and ribonuclease.
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PMID:Soluble adenylate cyclase from thyroid membranes. 67 Jan 96

Protein synthesis, normally a light-dependent process in isolated mature chloroplasts of Euglena gracilis var. bacillaris will take place in darkness if ATP and Mg2+ (ATP/Mg) are supplied. Either 5 or 10 mM ATP plus 15 mM MgCl2 are optimal and rates equal to those in the light can be obtained. Since ATP and Mg2+ are not stoichiometrically related, and since the optimal Mg2+ concentration is similar to that which stabilizes chloroplast ribosomes in vitro, it is suggested that the chloroplast is freely permeable to Mg2+ under these conditions. Protein synthesis under these conditions is not inhibited appreciably by DCMU, FCCP, cycloheximide, or by the addition of ribonuclease, but is highly sensitive to chloramphenicol. Carbon dioxide fixation is also a light-dependent process in isolated mature chloroplasts from Euglena, but addition of ATP (5 mM) and fructose bisphosphate (5 mM) plus aldolase (1.0 unit/ml) (fructose-1,6-bisphosphate/aldolase) yields CO2 fixation rates in darkness that are 43% of those normally obtained in the light. Mg2+ higher than 1.0 mM (e.g., 16 mM) is somewhat inhibitory. Chlorophyll synthesis from 5-aminolevulinate in 36 h developing chloroplasts from Euglena is also light-dependent, but addition of ATP/Mg and fructose-1,6-bis-phosphate/aldolase in darkness brings about the accumulation of a compound having the same RF on chromatography as protochlorophyllide from Barley; a subsequent brief illumination of the chloroplasts converts this compound to a compound with the RF of chlorophyll. Thus Euglena chloroplasts supplied with appropriate additions can carry out protein synthesis, carbon dioxide fixation and most of chlorophyll synthesis in darkness. This versatility is appropriate in photosynthetic organelles isolated from photo-organotrophic cells.
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PMID:Synthetic abilities of Euglena chloroplasts in darkness. 392 91

Experiments were run on three groups of healthy guinea pigs. One group was given ethionamide, kanamycin and PASA another was given ethionamide, kanamycin and pyrazinamide while the third served as a control. These studies permitted to establish that the above drugs affect the activity of enzymes involved in the metabolism of carbohydrates and nucleic acids. Activity of glucose-6-phosphatase and aldolase significantly decreased in liver, brain and lung tissue. At the same time, activity of deoxyribonuclease and ribonuclease in the tissues concerned sharply increased. Changes in activity of phosphohexose isomerase, lactate dehydrogenase and aminotransferases in these tissues was statistically insignificant.
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PMID:[Effect of various combinations of antibacterial drugs on enzyme activity in guinea pig tissues]. 531 14

The availability of very high magnetic fields of up to 170,000 gauss made it worthwhile to pursue the search for a critical change in the rate of four enzyme substrate reactions. The four enzymes were ribonuclease, polyphenol oxidase, peroxidase, and aldolase. The experiments showed that, to within +/-3%, no detectable change was observable in the rate of reaction of any of the systems for periods of exposure to the magnetic field of up to 20 min.
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PMID:Enzyme-substrate reactions in very high magnetic fields. I. 604 70

Models describing the interaction of a small molecule with a protein are typically couched in terms of the stoichiometry, cooperativity, and binding free-energy change. These parameters are readily available from equilibrium dialysis experiments (or appropriate variations). With the recent advent of extremely sensitive calorimeters, it is possible to obtain thermal data for the binding reaction and, thus, the entire set of thermodynamic parameters, delta G', delta H', delta S', delta C', become readily available. This review is limited to the binding of nucleotides and nucleotide analogs to proteins for which complete thermal data are available. While the majority of such systems have been characterized by calorimetry, we have not excluded, per se, van't Hoff enthalpy determinations. The systems we have considered include, but are not limited to, thymidylate synthetase, phosphorylase, several dehydrogenases, aldolase, glutamine synthetase, hemoglobin, asparate transcarbamylase, and ribonuclease. A variety of forces contribute to the total free-energy change upon ligand binding. These forces include ionic, van der Waals, hydrogen bond, and hydrophobic. In several cases, properly designed experiments have allowed a partial resolution of the individual contributions of these various forces. Variation of easily accessible conditions such as temperature, pH, ionic strength, or solvent third component produce changes in the set of thermodynamic parameters which lead to the resolution of the forces. The generality of heat effects makes this method very useful for studying the involvement of protons in binding reactions. The variation in the magnitude and direction (release or uptake) of the proton flux is readily studied by determining the apparent heat of reaction at constant pH, ionic strength, and temperature in two or more buffers of differing heat of ionization. This application has been exploited in several cases and is examined in great detail. An overview of the results in these systems to date suggests that several trends observed in the thermodynamic parameters need to be confirmed by further experimentation and, if they hold, an appropriate theoretical basis must be developed to aid in their interpretation.
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PMID:The thermodynamics of nucleotide binding to proteins. 610 94

Some cysteine-containing proteins upon sulfitolysis have been found to show anomalously retarded SDS-PAGE mobilities in non-reducing gels. These proteins include bovine serum albumin, ovalbumin, aldolase, ribonuclease and a recombinant fusion protein (XA) consisting of a portion of gamma-interferon linked to the A chain of human insulin. This mobility shift has been employed to determine the stability of the sulfonated products and to study the kinetics of the sulfitolysis reaction. Partially sulfonated products of intermediate shifts were observed at 0.01% beta-ME, while 0.05% beta-ME gave a shift characteristic of the completely reduced protein. The undiluted sulfitolysis reagent reacted with XA to give within 1 min a gel shift characteristic of the fully sulfitolysed protein. Its transition stages could be visualized at 15, 30 and 60 min when the reagent was diluted four-fold. In the presence of 8 M urea, the sulfitolysis of BSA was nearly complete at 30 min when the sulfitolysis reagent was used at a dilution of 1:5. However, under the same conditions BSA was predominantly unsulfitolysed in the absence of urea. In order to elucidate the mechanism of sulfonation shift, several derivatives of XA, e.g. performic acid oxidized, alkylated with (a) iodoacetamide and (b) iodoacetate, have been prepared. While the mobility of XASSO3- was sensitive to the presence of beta-ME, all other derivatives moved in a beta-ME-insensitive fashion. Furthermore, while the nonreducing mobilities of the acidic derivatives (-SSO3-, -SO3- and -SCH2CO2-) were anomalously retarded and identical, the mobility of the iodoacetamide derivative was intermediate between the retarded acidic derivatives above and XA below. These studies have suggested a role of the extended conformation of the A chain of insulin in causing a mobility shift of the acidic derivatives in this series. Similar results were observed in an analogous series of derivatives prepared from BSA. Non-denaturing gel filtration analyses of native vs. sulfitolysed samples of serum albumin, ovalbumin and ribonuclease have indicated that the sulfitolysed proteins elute earlier than their native counterparts and appear to be significantly larger than their true molecular weights. Circular dichroism analysis has indicated significant loss in helicity of sulfitolysed BSA. This suggests that the retarded mobility of sulfitolysed proteins seen on SDS-PAGE is likely to be due to an expansion in the hydrodynamic volumes of these proteins, a phenomenon triggered by cleavage of disulfide bonds and further accentuated by the introduction of strongly negatively charged sulfonates.
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PMID:Anomalous mobility of sulfitolysed proteins in SDS-PAGE. Analysis and applications. 889 91

Both full-length and subgenomic negative-strand RNAs are initiated at the 3' terminus of the positive-strand genomic RNA of the arterivirus, simian hemorrhagic fever virus (SHFV). The SHFV 3'(+) non-coding region (NCR) is 76 nts in length and forms a stem loop (SL) structure that was confirmed by ribonuclease structure probing. Two cell proteins, p56 and p42, bound specifically to a probe consisting of the SHFV 3'(+)NCR RNA. The 3'(+)NCR RNAs of two additional members of the arterivirus genus specifically interacted with two cell proteins of the same size. p56 was identified as polypyrimidine tract-binding protein (PTB) and p42 was identified as fructose bisphosphate aldolase A. PTB binding sites were mapped to a terminal loop and to a bulged region of the SHFV 3'SL structure. Deletion of either of the PTB binding sites in the viral RNA significantly reduced PTB binding activity, suggesting that both sites are required for efficient binding of this protein. Changes in the top portion of the SHFV 3'SL structure eliminated aldolase binding, suggesting that the binding site for this protein is located near the top of the SL. These cell proteins may play roles in regulating the functions of the genomic 3' NCR.
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PMID:Two cellular proteins that interact with a stem loop in the simian hemorrhagic fever virus 3'(+)NCR RNA. 1576 41

The importance of high-throughput analyses of protein abundances and functions is interestingly increasing in genomic/proteomic studies. In such postgenome sequencing era, a protein-detecting chip, in which a large number of molecules specifically capturing target proteins (capturing agents) such as antibodies, recombinant proteins, and small molecules are arrayed onto solid, wet, or semi-wet substrates, enables comprehensive analysis of proteomes by a single experiment. However, whole proteomes are generally complicated for comprehensive analyses so that alternative approaches to subproteome analysis categorized by protein functions and binding properties (focused proteome) would be effective. Approaching the goal of development of designed peptide chip for protein analysis, diversity increases in peptide structures and validation of target proteins are needed. We herein describe design and synthesis of nucleobase amino acid (NBA)-containing peptides, selection of nucleic acid-related proteins derived from S. cerevisiae, and detection of interactions between NBA-containing peptides and T7 phages displaying proteins by both enzyme-linked immunosorbent assays (ELISA) and label-free anomalous reflection of gold (AR) measurements. Twenty-eight phage clones were obtained by the phage-display method and sequenced. Ten of 28 clones were expected to be nucleic acid-related proteins including initiation factor, TYB protein, ribosomal proteins, elongation factor, ATP synthase subunit, GTP-binding protein, and ribonuclease. Other phage clones encoded several classes of enzymes such as reductase, oxidase, aldolase, metalloprotease, and hexokinase. Both ELISA and AR measurements suggested that the methodology of in vitro selection for recognition of the NBA-containing peptide presented in this study was successfully established. Such a combination of NBA and phage display technologies would be potential to efficiently confirm valuable target proteins binding specifically to capturing agents, to be arrayed onto solid surfaces to develop the designed peptide chip.
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PMID:Interactions between peptides containing nucleobase amino acids and T7 phages displaying S. cerevisiae proteins. 1720 24

The multifunctional proteins aldolase C and poly (A)-binding protein (PABP) undergo competitive interactions in cells coexpressing aldolase C and NF-L. A specific in vivo interaction between aldolase C and NF-L mRNA had been localized to a 68 nt segment of the transcript spanning the translation termination signal. It is shown here that the poly (A)-binding protein (PABP) binds the body of the NF-L transcript and increases its levels of expression when an excess of PABP is transiently provided in trans. Immunoprecipitation of PABP-associated ribonucleoprotein complexes of human spinal cord pulls down the dimeric form of aldolase C suggesting that their co-regulation of NF-L expression could be linked to the oligomerization status of aldolase C. An ex vivo model of mRNA decay has assessed mechanisms whereby aldolase C and PABP control NF-L expression. This model shows that aldolase C is a zinc-activated ribonuclease that cleaves the transcript at sites closed to the end-terminal structures. Immunological and biochemical depletion of endogenous PABP increases the instability of the transcript suggesting that PABP shields the NF-L mRNA from aldolase attack. An in vitro model shows that a mutant NF-L 68, in which the 45 nt of proximal 3'-UTR is replaced with unrelated sequence, is not degraded by aldolase C. Taken together, the findings might have important consequences for understanding causal mechanisms underlying neurodegeneration.
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PMID:Coregulation of light neurofilament mRNA by poly(A)-binding protein and aldolase C: implications for neurodegeneration. 1727 15


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