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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A single stained band containing approximately 5 micrograms of protein was cut out of a polyacrylamide gel and subjected to hydrolysis together with the gel. The hydrolysate was subsequently analyzed for its amino acid content by high-performance liquid chromatography and postlabeling with o-phthalaldehyde. Bovine serum albumin, ribonuclease B, ovalbumin, pepsin, and chymotrypsinogen A were analyzed by this method, and their amino acid compositions were found to be in good agreement with the reported values. By this method, it is possible to quantitate 16 amino acids: Asx, Thr, Ser, Glx, Pro, Cys, Gly, Ala, Val, Ile, Leu, Tyr, Phe, His, Lys, and Arg. Thioglycolic acid is effective protection against the decomposition of Tyr, Cys, and Met; however, the recovery of Met is inconsistent. This method might be very helpful for the amino acid analysis of proteins of multicomponent systems, especially, those which can be resolved only by polyacrylamide gel electrophoresis.
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PMID:Amino acid analysis by high-performance liquid chromatography of a single stained protein band from a polyacrylamide gel. 357 64

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

The ribonuclease resistance assay has been used to probe the effect of trypsin modification of the Escherichia coli elongation factor Tu X GTP on the interaction with E. coli aminoacyl-tRNAs. First, the equilibrium dissociation constant of the trypsin-modified Tu X GTP X Thr-tRNA complex was determined to be 2.3 (0.1) X 10(-5)M at 4 degrees C, pH 7.4. Second, binding of 17 of 20 noninitiator aminoacyl-tRNAs and four sets of purified isoacceptor tRNAs to the modified protein was measured. At 4 degrees C, the complex stabilities vary 500-fold over the range of aminoacyl-tRNAs, with Gln-tRNA forming the strongest ternary complex and Val-tRNA, the weakest. The results are compared to a similar study of ternary complex formation using intact elongation factor Tu X GTP, and the major differences are discussed. An analysis of both data sets, particularly that for the leucine isoacceptor tRNAs, suggests that the trypsin modification of elongation factor Tu X GTP disrupts a region of protein that is involved with the aminoacyl side chain rather than that of the acceptor stem helix region of the aminoacyl-tRNA.
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PMID:Effect of trypsin modification of the Escherichia coli elongation factor Tu on the ternary complex with aminoacyl-tRNA. 389 46

Parts of the amino acid sequences of horse and dromedary pancreatic ribonuclease were reinvestigated. The sequence of residues 21-25 in horse ribonuclease is Ser-Asn-Pro-Thr-Tyr or Ser-Asn-Ser-Thr-Tyr. The asparagine in the latter sequence is glycosylated. Horse ribonuclease possesses four additional amino acid residues at the C-terminus, like a number of other ribonucleases. Position 39 in horse and dromedary ribonuclease is not deleted but is occupied by tryptophan.
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PMID:Mammalian ribonucleases. The absence of a glycosylated Asn-Pro-Thr sequence in horse ribonuclease and the presence of tryptophan at position 39 in horse and dromedary ribonuclease. 392 90

A protein kinase which is intimately associated with equine herpesvirus (equine abortion virus) was found by using adenosine triphosphate-gamma-(32)P as a phosphate donor and virus protein as an acceptor. Consistent demonstration of the activity requires prior removal of phosphohydrolase. The kinase activity requires Mg(2+), is not stimulated by cyclic adenosine monophosphate, but is enhanced by added protamine or arginine-rich histone. The labeled product is resistant to ribonuclease, deoxyribonuclease, and chloroform-methanol but is sensitive to Pronase. Other tests suggest that serine and threonine residues are the acceptor sites. In the in vitro reaction, the incorporation represents an average of approximately 4,500 phosphate residues per virion, and all 17 virus protein bands resolved by polyacrylamide gel electrophoresis appear to be labeled.
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PMID:Protein kinase activity in equine herpesvirus. 433 15

Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3-10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase, beta-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.
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PMID:Purification and partial characterization of four proteins from human parotid saliva. 500 93

Young rats were force-fed for 3 days a purified diet devoid of threonine and a number of aspects relating to RNA metabolism in the livers were studied. The findings in the livers of rats force-fed the threonine-devoid diet in comparison with those force-fed the complete diet were as follows: a) poly(A)-mRNA was increased in nuclei and in polyribosomes; b) DNA-dependent RNA polymerases I and II activities were increased; c) in vitro release of 14C-orotic acid labeled RNA from nuclei revealed that transport was unchanged and nucleoside triphosphatase activity of nuclear envelopes was unchanged; d) polyribosomes (total, free and membrane-bound) shifted toward heavier aggregation and in vitro 14C-leucine incorporation into protein was increased; e) RNase activities (at pH 5.4, 7.6, 9.5) were essentially unaltered; and f) in vivo 14C-choline incorporation into microsomal membranes was increased. By administering selected inhibitors of RNA and protein synthesis, such as actinomycin D, alpha-amanitin or cycloheximide, prior to killing the rats force-fed the threonine-devoid or complete diet for 3 days, it was demonstrated that the stimulatory effect on hepatic polyribosomes and protein synthesis in the experimental group was dependent upon new synthesis of poly(A)mRNA and of protein.
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PMID:Studies dealing with hepatic RNA metabolism in rats force-fed a threonine-devoid diet. 616 Feb 24

The substrate specificity of pancreatic ribonuclease A is discussed in light of observations based on accurate X-ray structure analysis of several enzyme-nucleotide complexes. A hypothesis for protein-nucleic acid recognition is presented which proposes that: (a) pyrimidine bases in RNA are recognised by ribonuclease due to the charge complementarity of two groups (the amide nitrogen and the side chain oxygen (OG) of threonine 45) of the protein and relevant atoms in the heterocyclic base (O2 and N3 in pyrimidine nucleotides); (b) interaction of the protein with the ribose moiety of the nucleotides is non-specific; and (c) conformational flexibility in the region of the scissile P-O bond is provided by different locations of the phosphoryl oxygens, rather than by an overall translation of the phosphate moiety.
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PMID:Enzyme specificity: base recognition and hydrolysis of RNA by ribonuclease A. 619 18

The primary structure of human (Homo sapiens) pancreatic ribonuclease has been determined by automatic sequencing of the native protein and by analysis of peptides obtained by cleavage with proteolytic enzymes, cyanogen bromide, and hydroxylamine. The following sequence was deduced: (sequence in text). Human pancreatic ribonuclease differs at 37 positions from bovine pancreatic ribonuclease. In addition the human enzyme has three more residues at the C-terminus. About half of the enzyme molecules contain carbohydrate attached to the sequence Asn-Met-Thr (34-36). Two other Asn-X-Ser/Thr sequences are carbohydrate free. Human pancreatic ribonuclease contains many positively charged residues, especially near the N-terminus, while negatively charged residues are more concentrated near the C-terminus.
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PMID:The amino acid sequence of human pancreatic ribonuclease. 620 Oct 87

Difference Fourier maps have been calculated at 2.8-A resolution by using neutron diffraction data obtained from a single crystal of RNase A. The phases were derived from a model resulting from the joint refinement of x-ray and neutron data at 2.0-A and 2.8-A resolution, respectively. The orientation of histidine-48 assumed during the refinement of the x-ray model at 2.5 A was confirmed, whereas the other three histidines had to be rotated around C beta--C gamma bonds in order to agree with the neutron difference Fourier maps. In the final model, histidine-12 is clearly hydrogen bonded to the carbonyl oxygen of threonine-45 and to the oxygen of the inorganic phosphate, and histidine-119 is bonded to another oxygen of the phosphate and to the oxygen OD1 of aspartic acid-121.
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PMID:Orientation of histidine residues in RNase A: neutron diffraction study. 626 17


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