Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Incubation of Neurospora crassa conidia with ribonuclease (RNase) A reduces transport of L-phenylalanine by those cells. Under similar conditions, oxidized RNase A, RNase T1, and RNase T2 do not have this effect. Incubation of conidia with active RNase covalently attached to polyacrylamide beads reduces L-phenylalanine transport. This indicates that the site of enzymatic action is at the cell surface. At the lower concentration of enzyme used in this study, incubation with RNase A reduces transport of L-phenylalanine by the general (G) amino acid permease. Increasing the enzyme concentration results in reduction of transport by the neutral aromatic (N)-specific permease. The increased transport activity that accompanies onset of conidial germination is also sensitive to incubation with RNase A. Application of the enzyme to actively transporting cells does not release amino acid transported prior to enzyme addition. Cells cultured on media supplemented with [2-14C] uridine release isotopic activity after RNase A incubation. Analogous treatments with Pronase, RNase T1, RNase T2, or deoxyribonuclease I do not release isotope activity. Pronase treatment does reduce L-phenylalanine transport. Incubation of conidia with RNase A also inhibits germination of those conidia.
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PMID:Effects of ribonuclease A on amino acid transport in Neurospora crassa. 12 24

This paper demonstrates the existence of regions in eight small globular proteins in which the side chains of sulfur-containing amino acids (cysteine and methionine) alternate in space with side chains of aromatic amino acids (histidine, phenylalanine, tryptophan and tyrosine). The proteins are: rubredoxin, high potential iron protein, cytochrome c, flavodoxin, deoxyhemoglobin, trypsin inhibitor, ribonuclease-S, and lysozyme. The sulfur-pi-bonded 'chains' involve a minimum of five and a maximum of 10 amino acids, and contain the most polarizable atoms within proteins. S-pi-chains give extra stability to the folding of proteins; they may also afford paths for the step-wise movement of electrons.
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PMID:Chains of alternating sulfur and pi-bonded atoms in eight small proteins. 20 19

M protein was extracted from type 24, group A streptococci with pepsin at pH 5.8 and was further purified by ammonium sulfate precipitation, ribonuclease digestion, ion-exchange chromatography, and isoelectric focusing. The purified pepsin extract of M (pep M) protein was shown to be free of nontype-specific immunoreactivity in (a) complement fixation tests with heterologous M antiserum, (b) skin tests in normal adult guinea pigs, and (c) passive hemagglutination tests for the presence of lipoteichoic acid sensitizing or antigenic activity. The pep M24 was highly immunogenic; two of three rabbits developed opsonic antibody titers of 1:256 and the third a titer of 1:32 6 wk after a single injection of 100-pg doses of pep M24 emulsified in complete Freund's adjuvant. The antisera lacked nontype-specific antibodies and produced single precipitin lines in agar gel diffusion tests against crude HC1 extracts of the homologous M protein. Thus, the type-specific antigenic determinant(s) of type 24 M protein appears to be separable from immunotoxic, cross-reactive antigens without loss of immunogenicity in rabbits. The mobility of pep M24 upon electrophoresis in 10 percent sodium dodecyl sulfate pelyacrylamide gel was consistent with an average mol wt of 33,500 daltons. Amino acid analysis demonstrated a predominance of alanine, followed by glutamic acid, lysine, leucine, and aspartic acid. Pep M24 contained an estimated six to seven methionine residues and approximately ten phenylalanine residues per molecule. No other aromatic amino acids were detected. Automatic Edman degradation of pep M24 yielded the sequence of the first 29 amino acids (the amino terminal amino acid being valine) of the amino terminal region of the molecule. The detection of only one new amino acid at each step of Edman degradation confirmed the homogeneity of the purified pep M24.
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PMID:Purification and properties of M protein extracted from group A streptococci with pepsin: covalent structure of the amino terminal region of type 24 M antigen. 32 68

The second derivative absorption spectra of serum albumin, insulin, ribonuclease and lysozyme were measured under various conditions to determine the state and amount of their phenylalanine residues. The second derivative spectra of these proteins were very similar to that of phenylalanine in the region between 245 and 270 nm where tryptophan and tyrosine residues caused no appreciable interference. Denaturation of proteins with urea or guanidine hydrochloride caused decrease in the intensity of the second derivative spectra, but scarcely affected the positions of peaks and troughs. The amounts of phenylalanine residues in proteins calculated from a second derivative spectra of denatured proteins coincided well with those reported in the literature. The states of the phenylalanine residues in the proteins could be deduced from the change in optical intensity on denaturation.
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PMID:Estimation of state and amount of phenylalanine residues in proteins by second derivative spectrophotometry. 39 35

The characteristics of an in vitro polyuridylic acid dependent amino acid incorporating system prepared from germinating macroconidia of Microsporum canis are described. The incorporation of 14C-phenylalanine into polyphenylalanine is dependent on S-30 extract, adenosine triphosphate, magnesium ions and polyuridylic acid. Incorporation is slightly enhanced by yeast transfer ribonucleic acid and pyruvate kinase. The system is highly sensitive to ribonuclease, puromycin and miconazole (an antifungal agent), moderately sensitive to sodium fluoride and much less sensitive to phenethylalcohol, cycloheximide, chloramphenicol and deoxyribonuclease. Cell-free extract from ungerminated conidia has less capacity to synthesize the protein and during germination a marked increase in the protein synthetic activity is observed. The results from experiments wherein ribosomes and S-100 fraction from germinated and ungerminated spores are unterchanged, revealed that the defect in the extract from the ungerminated spore is in the ribosomes.
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PMID:Studies on the macroconidia of Microsporum canis. Characteristics of in vitro amino acid incorporating system. 42

(1) The regulation of the accumulation of the isoflavonoid-derived phytoalexin phaseollin in cell suspension cultures of Dwarf French Bean (Phaseolus vulgaris/ has been investigated. (2) An elicitor preparation from cell walls of Colletotrichum lindemuthianum, the causal agent of anthracnose disease of French bean, caused a marked accumulation of phaseollin in the cultures. The elicitor induced phaseollin accumulation to a level of 60% that obtained with the artificial elicitor autoclaved ribonuclease A and was maximally active at a concentration (weight basis) of at least 50 times lower than required for maximal response to ribonuclease. (3) Elicitor preparations from cell walls of Phytophthora megasperma var. sojae, a fungal pathogen of soybean, and Botrytis cinerea, the common grey mould, were much less effective than the C. lindemuthianum wall-released elicitor. (4) There was a marked but transient increase in the extractable activity of phenylalanine ammonia-lyase, the enzyme catalysing the first reaction in the biosynthesis of phaseollin from L-phenylalanine, in response to the elicitor from C. lindemuthianum. (5) Comparative density labelling with 2H from 2H2O indicated that the elicitor stimulates de novo synthesis of phenylalanine ammonie findings provide the basis of a scheme for elicitor induction of phytoalexin accumulation.
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PMID:Stimulation of de novo synthesis of L-phenylalanine ammonia-lyase in relation to phytoalexin accumulation in Colletotrichum lindemuthianum elicitor-treated cell suspension cultures of french bean (Phaseolus vulgaris). 47 49

A description is given of the synthesis by fragment condensation of the peptide Gly-Glu-Ser-Arg-Glu-Ser-Ser-Ala-Asp-Lys-Phe-Lys-Arg-Gln-His-Met-Asp-Thr-Glu-Gly-Pro-Ser-Lys corresponding to the 1--23 amino acid sequence of rat pancreatic ribonuclease. This rat peptide combined with bovine S-protein yields a fully active ribonuclease S' analogue.
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PMID:Studies on polypeptides. XXVI. Synthesis of the N-terminal 1--23 peptide sequence of rat pancreatic ribonuclease; enzymatic activity of the hybrid complex with bovine S-protein. 64 56

Investigation of the known protein structures has led to the generalization that the native folding permits each sidechain to select those nearest-neighbors which maximize stabilization from van der Waals interactions. With regard to secondary structure: 1. Helical and beta regions exhibit characteristic patterns of short-range contacts (residue numbers k and k + t with [t] less than or equal to 4) due to the geometries of these secondary structures. However, these are not strictly obligatory, and preferred short-range contacts which would result in unfavorable van der Waals interactions are replaced by favorable long-range contacts. 2. The generalization mentioned at the outset holds for individual proteins, both for short-range and long-range contacts, and without regard for the type or amount of secondary structure present. 3. These observations imply that van der Waals interactions arising from short-range contacts partially determine secondary structure, and this is demonstrated by tests based upon assignment of regions of secondary structure in the known proteins. The principle of optimizing van der Waals stabilization from long-range contacts is applied to predict the structure of the complex formed by the S-peptide and S-protein of ribonuclease-S. The formation of favorable pairs is found to be more important than the total number of intermolecular contacts, and 40 to 50% of this stabilization is contributed by two residues of the S-peptide, Phe-8 and Met-13.
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PMID:Local interactions as a structure determinant for protein molecules: III. 76 Aug 7

Chromatography of commercial rennet was studied on biospecific sorbents obtained by means of coupling of activated Sepharose 4B with epsilon-aminocapronyl-D-phenylalanine methyl ester and amide, epsilon-aminocapronyl-L-phenylalanyl-D-phenylalanine methyl ester, gramicidin S and N-2,4-dinitrophenylhexamethylenediamine. A mixture of two similar on their specificity enzymes chymosin and bovine pepsin was isolated from rennet by the chromatography on these sorbents. The individual enzymes might be isolated by chromatography on immobilized ribonuclease at pH 3,0, or by means of electrofocusing in pH gradient 4-6. Coloured inhibitor of acid proteases, N-diazoacetyl-N'-2,4-dinitrophenyl-ethylenediamine (DDE) is found to inactivate chymosin at pH 5,6 in the presence of Cu2+,one residue of the inhibitor being attached to the enzyme molecule. Unlike pig pepsin, chymosin is not inhibited with DDE at pH 4,7 and at the enzyme:DDE:Cu2+ ratio being 1:40:40. a synthesis of peptide sorbents is described.
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PMID:[Biospecific chromatography of chymosin]. 77 34

Syntheses are described of two S-peptide analogues where the arginyl residue in position 10 has been replaced by ornithine and the phenylalanine in position 8 has been substituted by the unnatural amino acids cyclohexylalanine or p-fluorophenylalanine. In order to regenerate the arginyl residue, which is present in position 10 in the natural sequence, the S-peptide analogues beloning to the [Orn10]-series are transformed into the corresponding guanidinated derivatives by treatment with O-methylisourea. 1epsilon, 7epsilon, 10delta triguan-[Cha8, Orn10]-, 1epsilon, 7epsilon, 10delta-triguan-[pF-Phe8, Orn10]- and 1epsilon, 7epsilon, 10delta-triguan-[Tyr8, Orn10]-S-peptides were prepared. The ability to bind to and activate the S-protein of the synthetic S-peptide analogues, before and after guanidination, was tested by exploring their capacity to generate ribonuclease activity using RNA and C greater than p as substrates. The affinity of the different peptides for the S-protein in the absence of substrate was evaluated by difference spectroscopy.
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PMID:Kinetic and conformational studies on some partially synthetic ribonuclease S' analogues modified in position 8. 88 Dec 90


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