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

---

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

Comparisons of the primary structures of 18S and 28S ribosomal RNAs of man, rat, mouse and chicken were made by two-dimensional fractionation including electrophoresis at pH 3.5 and homochromatography. All large T1 oligonucleotides were recovered from the different fingerprints and their radioactivity was measured. They were then hydrolysed with pancreatic RNase and the pancreatic products were digested with alkali to determine their base composition and detect modified residues. Finally, residues bearing a modification on the ribose were analysed by hydrolyses with snake venom and spleen phosphodiesterases. For the 18A RNAs 23, 27, 26, 24 oligonucleotides, whose lengths range from 22 to 10 residues, were analyzed respectively for man, rat, mouse and chicken. Among these, 14 are identical in the four species, two at least are common to man, rat, mouse but differ by the presence of A-Cps in chicken spot 4' instead of A-Up in spot 4 and A2-Gp in chicken spot 14 instead of A2-Gp in spot 13. For the 28S RNAs of man, rat, mouse and chicken, 20, 19, 21 and 22 oligonucleotides ranging in length from 27 to 12 residues were analyzed. 11 of them are common to the four species; 4 of them are found in man, rat, mouse and one of these (spot 1) has a corresponding spot in chicken from which it differs only by the existence of A3-Up instead of A2-Up. Another mammalian oligonucleotide (spot 6) differs from its homologous chicken spot (spot 6') bytwo point mutations. The same modified residues as found by Khan and Maden in man, chicken, and xenopus, have been found in rat and mouse. Moreover when these modified residues are common to several species they are found within an identical nucleotide sequence, as can be seen in the case of spots 1, 3, 9, 11 of 18S RNAs and 4, 7, 13 for 28S RNAs. The number of differences observed between the ribosomal RNAs of the four species were compared to the number of differences observed in the same species for several proteins, globins alpha and beta, insulin, cytochrome C and lysozyme.
...
PMID:Comparative studies of the primary structures of ribosomal RNAs of several eukaryotic cell lines by the fingerprinting method. 11 49

The protein spin-echo decay and recovery of longitudinal magnetization were studied in seven globular proteins: cytochrome C, ribonuclease, lysozyme, DNA, hemoglobin, serum albumin and gamma-globulin in D2O solutions. For comparison the Tobacco mosaic virus (TMV) protons in D2O solutions were also investigated. The spin-echo decay of all 7 proteins can be separated into three components: a slowly decaying component with an amplitude of about 10% of the amplitude of the total signal, intermediately and fastly decaying components, the two latter being comparable in amplitudes. Longitudinal relaxation is more simple in character. The value of T2 of the protons responsible for the fastly decaying components in linearly dependent on the molecular weight of the protein, a fact indicating that the regions of the proteins with a "rigid" structure can be responsible for this component. The intermediate component, whose contribution increases with temperature, was ascribed to the mobile regions of the protein, and the slowly decaying component to the mobile protein side chains. Weak dependence of T1 on the protein molecular weight and some other obtained data give additional evidence for the presence of motion within macromolecules. The peculiarities of this motion is in good correspondence with the notion about the existence of the segmental motion of the polypeptide chain (conformational mobility of the protein). In contrast to proteins the spin-echo decay of TMV lacked the slow component and the "solid" echo signal was observed which indicates the existence of a "rigid" structure in the macromolecules of the virus.
...
PMID:[Study of the conformational mobility of globular proteins by pulse methods of NMR]. 20 75

Chloroplasts, isolated from the leaves of 7-day-old pea seedlings, were incubated in the light with [35S]methionine or [3H]leucine. After extraction from the washed chloroplast membranes using a mixture of ethyl acetate, ethanol and ammonia, cytochrome f was precipitated with a monospecific antiserum and resolved by gradient polyacrylamide gel electrophoresis in sodium dodecylsulphate. The cytochrome f band was identified by its intrinsic fluorescence in ultraviolet light and was shown to be radioactive by autoradiography or fluorography of dried polyacrylamide gel. One-dimensional peptide mapping of the products of papain hydrolysis confirmed that the radioactivity was an integral part of cytochrome f. The incorporation of [35S]methionine into cytochrome f was inhibited by D(-)threo-chloramphenicol but not by cycloheximide and did not occur in the dark. The synthesis was resistant to ribonuclease. It is concluded that cytochrome f is synthesised in intact isolated pea chloroplasts.
...
PMID:Synthesis of cytochrome f by isolated pea chloroplasts. 46 51

The addition of cationic proteins such as lysozyme, ribonuclease and cytochrome C enhanced the beta-lactam-induced bacteriolysis of staphylococci measured as release of wall label or by optical density. The treatment of staphylococci with penicillin plus cytochrome C resulted in a reduced viability of bacteria compared with those treated with penicillin alone. The wall autolysis and the penicillin-induced bacteriolysis of staphylococci were enhanced by the lysosomal enzyme cathepsin C. The penicillin-induced bacteriolysis was also enhanced by the D-amino acids D-alanine and D-methionine, while the comparable L-amino acids did not reveal any activity. On the other hand, some polyanionic substances were able to suppress the penicillin-induced bacteriolysis. Radiochemical and electron microscopic studies revealed the participation of bacterial wall autolysins in the first steps of degradation processes of staphylococcal walls within murine bone marrow-derived macrophages.
...
PMID:The modulation of the bacteriolytic effect of beta-lactam antibiotics by non-antibiotics. 129 43

An automated method for the optimal placement of polar hydrogens in a protein structure is described. This method treats the polar, side chain hydrogens of lysine, serine, threonine, and tyrosine and the amino terminus of a protein. The program, called NETWORK, divides the potential hydrogen-bonding pairs of a protein into groups of interacting donors and acceptors. A search is conducted on each of the local groups to find an arrangement which forms the most hydrogen bonds. If two or more arrangements have the same number of hydrogen bonds, the arrangement with the shortest set of hydrogen bonds is selected. The polar hydrogens of the histidyl side chain are specifically treated, and the ionization state of this residue is allowed to change, if this change results in additional hydrogen bonds for the local group. The program will accept Protein Data Bank as well as Biosym-format coordinate files. Input and output routines can be easily modified to accept other coordinate file formats. The predictions from this method are compared to known hydrogen positions for bovine pancreatic trypsin inhibitor, insulin, RNase-A, and trypsin for which the neutron diffraction structures have been determined. The usefulness of this program is further demonstrated by a comparison of molecular dynamics simulations for the enzyme cytochrome P-450cam with and without using NETWORK.
...
PMID:A method for determining the positions of polar hydrogens added to a protein structure that maximizes protein hydrogen bonding. 137 79

We have examined the tissue-specific expression and inducibility of acyl-CoA oxidase and cytochrome P450IVA1 (P450IVA1) RNA in rats. Groups of three rats were dosed daily by gavage with methylclofenapate at 25 mg/kg in 5 ml/kg corn oil for nine weeks, or were administered a vehicle control. P450IVA1 and acyl-CoA oxidase RNA were detected using an RNase protection assay. Similar levels of acyl-CoA oxidase RNA were present in control liver and kidney, but the level of this RNA in lung, muscle and testis was 6-11%, and in pancreas was 0.13%, of that in liver. Treatment of rats with methylclofenapate led to an 11-fold induction of acyl-CoA oxidase RNA in liver and also produced a significant induction of this RNA in kidney, lung, muscle and testis of 1.7-fold, 1.3-fold, 2-fold and 1.7-fold, respectively. Acyl-CoA oxidase RNA was not induced in pancreas. P450IVA1 RNA was present in control liver and also in kidney of control rats at 28% of the level in liver. In contrast to acyl-CoA oxidase RNA, P450IVA1 RNA was not detected in lung, pancreas or testis. Methylclofenapate treatment of rats led to an 18-fold induction of P450IVA1 RNA in liver, and a sevenfold induction in kidney. Induction of P450IVA1 was not detected in any of the other tissues examined. Quantification of the relative amounts of acyl-CoA oxidase and P450IVA1 RNA in control liver revealed that acyl-CoA oxidase RNA was present in a 17.5-fold molar excess over P450IVA1 RNA. Western blotting with an anti-P450IVA IgG revealed two bands of similar apparent molecular mass in liver and kidney microsomes, but not in microsomes from the testis of control rats. Methylclofenapate treatment of rats caused an increase in the intensity of these bands in microsomes from liver, but no induction was obvious in kidney. Immunocytochemical staining for both the microsomal P450IVA and peroxisomal acyl-CoA oxidase proteins was restricted to the proximal convoluted tubule in the kidney cortex, with staining being most intense in the S3 region.
...
PMID:Differential tissue-specific expression and induction of cytochrome P450IVA1 and acyl-CoA oxidase. 137 90

Cytochrome d has been postulated to be the "respiratory protection" oxidase of Azotobacter vinelandii, allowing this organism to fix nitrogen under aerobic growth conditions. We have previously cloned and characterized the structural genes for the A. vinelandii cytochrome d (cydA and cydB). The cyd genes are co-transcribed, yielding an mRNA of approximately 3.6 kilobase pairs. The level of the cyd message was 2-3-fold higher in cells that were fixing nitrogen, as compared with non-nitrogen-fixing cells. RNase protection analysis was used to determine the transcriptional start site at 275 bases upstream of the initiator ATG of cydA, and this start site was the same for nitrogen-fixing and non-nitrogen-fixing cells. The cyd promoter has sequence similarities to the canonical Escherichia coli promoters, which are transcribed by the major sigma 70 form of RNA polymerase. Plasmid-borne lacZ transcriptional fusions were constructed, using approximately 650 base pairs of 5'-upstream sequences of the cyd structural genes. This region had a strong promoter activity which was further up-regulated 1.5-2.5-fold upon the induction of nitrogen fixation. The cyd-lacZ fusions were characterized in a nifA- as well as an ntrA- background. Mutations in neither of these nif regulatory genes affected the constitutive expression of cyd under non-nitrogen-fixing conditions. However, the up-regulation of this promoter during the induction of nitrogen fixation was abolished only in the ntrA- background. Based on these results, the cytochrome d promoter of A. vinelandii belongs to a new class of nitrogen-regulated promoters which, unlike the authentic nif genes, does not require the ntrA gene product for its expression. The up-regulation of this promoter during nitrogen fixation, however, requires the ntrA gene product.
...
PMID:Transcriptional regulation of cytochrome d in nitrogen-fixing Azotobacter vinelandii. Evidence that up-regulation during N2 fixation is independent of nifA but dependent on ntrA. 166 Apr 68

Multidrug-resistance (MDR) genes are induced in the liver of rodents treated with a variety of foreign chemicals and hepatocarcinogens. It has been reported that 2,3,6,7-tetrachlorodibenzo-p-dioxin (TCDD) might increase hepatic MDR transcripts in the Fischer rat and the C57BL/6 (B6) inbred mouse strain having the high-affinity aromatic hydrocarbon (Ah) receptor, but not in the DBA/2 (D2) strain having the low-affinity Ah receptor. These intriguing results suggest that TCDD might activate MDR gene expression by way of an Ah receptor-mediated signal transduction pathway. We have attempted to confirm these data in four inbred mouse strains: two (B6 and BALB/c) having the high-affinity Ah receptor, and two (D2 and AKR) having the low-affinity Ah receptor. The RNase protection assay was used to distinguish between the MDR1, MDR2, and MDR3 mRNAs. TCDD treatment at high (100 micrograms/kg) and low (1 mu/kg) doses, a time course from 6 to 96 hr of TCDD treatment, progeny from the B6D2F1 x D2 backcross, and transcriptional run-on experiments were performed. The Cyp1a-1 (cytochrome P1450) and Nmo-1 [NAD(P)H:menadione oxidoreductase] genes, two members of the TCDD-inducible [Ah] battery, were used as positive controls. We were unable to detect significant coinduction of MDR1, MDR2, or MDR3 mRNA with CYP1A1 mRNA or with Cyp1a-1 or Nmo-1 transcription under any conditions. Therefore, we conclude that any effects that TCDD might have on MDR expression must be substantially different from TCDD effects on genes known to be induced via the Ah receptor.
...
PMID:Murine mdr-1, mdr-2, and mdr-3 gene expression: no coinduction with the Cyp1a-1 and Nmo-1 genes in liver by 2,3,7,8-tetrachlorodibenzo-p-dioxin. 206 18

Mouse MA-10 Leydig tumor cells synthesize and secrete progesterone in response to human chorionic gonadotropin, luteinizing hormone, and cAMP but may not synthesize androgens. Maximal doses of human chorionic gonadotropin, ovine luteinizing hormone, forskolin, or 8-bromoadenosine 3',5'-cyclic monophosphate, stimulated cytochrome P450scc mRNA accumulation 1.5- to 3-fold and progesterone secretion 10- to 100-fold in MA-10 cells. P450scc mRNA increased by 2 hr and was maximal by 8 hr; polymerase run-on experiments showed this was due to increased P450scc gene transcription. MA-10 cells are a hormonally homogeneous population, as all cells expressed P450scc mRNA and responded to cAMP equally. cAMP-stimulated accumulation of P450scc mRNA continued in the presence of cycloheximide. Gonadotropins stimulated testicular steroidogenesis by coordinate cAMP-induced increases in P450scc gene transcription, mRNA accumulation, and P450scc activity. We cloned rat P450c17 cDNA and showed it detected no P450c17 mRNA in control or cAMP-stimulated MA-10 cells by RNA transfer blots or RNase protection assays. Similarly, HPLC detected no 17 alpha-hydroxyprogesterone or testosterone synthesis in MA-10 cells. Thus MA-10 cells, unlike untransformed Leydig cells, do not express detectable amounts of P450c17 mRNA or P450c17 activity.
...
PMID:cAMP regulates P450scc gene expression by a cycloheximide-insensitive mechanism in cultured mouse Leydig MA-10 cells. 255 89

To determine whether tubular reabsorption of low molecular weight proteins (LMWPs) alters ischemic tubular injury, rats were infused with 25 mg of lysozyme (isoelectric point (pI) 11.3), cytochrome C (pI 10.6), ribonuclease (pI 8.7), or myoglobin (pI 7.0), and during this time 25 minutes of bilateral renal artery occlusion (RAO) was induced. RAO control rats received either saline or 25 mg of albumin. Renal injury was assessed 24 hours later by blood urea nitrogen, creatinine, and histology. Lysozyme, ribonuclease, and myoglobin each exacerbated ischemic damage (increased tubular necrosis, cast formation, azotemia), but to comparable degrees (e.g., blood urea nitrogen range 75 +/- 8 to 100 +/- 5 mg/dl versus controls, 29 +/- 2 to 36 +/- 7; p less than 0.01). Rendering lysozyme anionic (pI 4.5) by succinylation did not diminish its acute renal failure-potentiating effect. Cytochrome C which is freely filtered but poorly reabsorbed had a minimal impact on the ischemic process. Infusion of LMWPs did not alter blood pressure, renal blood flow, or induce renal injury in the absence of RAO. During a sublethal ischemic event (10 minutes of RAO) LMWP infusion exacerbated proximal tubular luminal membrane damage before an adverse effect on other critical determinants of cell integrity were apparent (adenine nucleotide pools, oxidant stress). We conclude that endocytic LMWP reabsorption by proximal tubules can exacerbate superimposed ischemic tubular necrosis independent of any direct nephrotoxic protein effect. This action is not influenced by protein isoelectric point and appears to be mediated by a primary intensification of ischemic luminal membrane damage.
...
PMID:Low molecular weight proteinuria exacerbates experimental ischemic renal injury. 380 17


1 2 3 4 5 6 Next >>

---