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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transglutaminase from guinea pig liver catalyzed the formation of cross-links between fibrinogen (or fibrin) and ribonuclease. Using transglutaminase, immoblized ribonuclease was prepared by two separate methods: (1) fibrinogen-ribonuclease conjugates formed by transglutaminase were treated with thrombin to make fibrin membrane bound covalently to the enzyme; (2) fibrin polymer formed from fibrinogen with thrombin was covalently bound to ribonuclease by transglutaminase to make fibrin-ribonuclease conjugates.
...
PMID:Fibrin membrane endowed with biological function. IV. Formation of cross-links between fibrinogen (or fibrin) and ribonuclease by transglutaminase. 3 50

The release of protein disulfide isomerase by activated platelets was hypothesized on the basis of reported intermolecular and intramolecular thiol-disulfide exchange and disulfide reduction involving released thrombospondin in the supernatant solution of activated platelets (Danishefsky, Alexander, Detwiler: Biochemistry, 23:4984, 1984; Speziale, Detwiler: J Biol Chem, 265:17859, 1990; Speziale, Detwiler: Arch Biochem Biophys 286:546, 1991). Protein disulfide isomerase activity, measured by catalysis of the renaturation of ribonuclease inactivated by randomization of disulfide bonds, was detected in the supernatant solution after platelet activation. The activity was inhibited by peptides known to inhibit protein disulfide isomerase; the peptides also inhibited formation of disulfide-linked thrombospondin-thrombin complexes. The reaction catalyzed by the supernatant solution showed a pH dependence distinct from that of the uncatalyzed reaction. The activity was excluded by a 50-Kd dialysis membrane, and it was eluted in the void volume of a gel-filtration column, indicating that it was associated with a macromolecule. The activity was not removed by centrifugation at 100,000 g for 150 minutes indicating that it was not associated with membrane microvesicles. Possible functions for the release of protein disulfide isomerase by activated platelets are discussed.
...
PMID:Protein disulfide isomerase activity is released by activated platelets. 157 38

Fibroblasts represent one of the in vivo sites of insulin-like growth factor-I (IGF-I) production. In this study rat dermal fibroblasts in culture were used as a model system to assess the effect of activation of protein kinase-C on the levels of the mRNAs encoding IGF-I and another growth factor, basic fibroblast growth factor (bFGF). IGF-I and bFGF mRNA levels were determined using a solution hybridization/RNase protection assay. Treatment of cells in serum-free medium containing 0.25% BSA (MEM + BSA) with the tumor-promoting phorbol ester phorbol 12-myristate 13-acetate (PMA) decreased IGF-I and increased bFGF mRNA levels in a time- and dose-dependent fashion. The peak effect of 100 nM PMA on IGF-I mRNA levels occurred at 9 h, whereas the peak effect on bFGF mRNA levels occurred after 3 h of incubation. In dose-response studies, half-maximal inhibition of IGF-I mRNA levels was achieved with approximately 0.08 nM PMA, while half-maximal stimulation of bFGF mRNA levels was achieved with approximately 3 nM PMA. Inhibition of protein synthesis with cycloheximide abrogated the effect of PMA on bFGF mRNA levels, but only partially inhibited the effect of PMA on IGF-I mRNA levels. Studies employing sphingosine or staurosporine to inhibit protein kinase-C or preincubation in high doses of PMA to down-regulate protein kinase-C suggested that the effect of PMA on IGF-I and bFGF mRNA levels was mediated by activation of protein kinase-C, although both staurosporine and sphingosine had independent effects on the levels of these mRNAs and down-regulation of protein kinase-C had a sustained effect on IGF-I mRNA levels. Ligands known to activate protein kinase-C were then tested. Treatment of cells with 100 micrograms/ml of the synthetic diacylglycerol 1-oleoyl-2-acetyl-sn-glycerol decreased IGF-I mRNA levels to 25% and increased bFGF mRNA levels to 520% of the level present in cells maintained in MEM + BSA. Treatment of cells with thrombin or bradykinin also decreased IGF-I mRNA levels and increased bFGF mRNA levels, but whereas the effect of thrombin on IGF-I mRNA levels was marked, the effect of bradykinin was minimal, and whereas the effect of thrombin on bFGF mRNA levels was sustained, the effect of bradykinin was transient.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Activation of protein kinase-C differentially regulates insulin-like growth factor-I and basic fibroblast growth factor messenger RNA levels. 160 84

Antithrombin III (ATIII) is a plasma-borne serine protease inhibitor that plays a pivotal role in the regulation of hemostasis. The cDNA for ATIII has been available, but genetic studies on the functional domains of ATIII have not progressed because of the absence of an expression system that will yield sufficient quantities of biologically active protein for biochemical analyses. In the present studies the cDNA of the human antithrombin III gene was inserted into the vector pVL 1393, which is suitable for cotransfection of Spodoptera frugiperda (Sf9) insect cells with Baculovirus wild-type DNA. Recombinant virus particles were selected by the presence of occlusion-negative plaques. Upon infection with purified recombinant virus, Sf9 cells secreted 10-35 micrograms of ATIII/1 x 10(6) cells. Southern analysis of DNA from infected cells demonstrated incorporation of the full-length cDNA into the Baculovirus recombinant, and RNase protection experiments verified the presence of full-length transcript. This recombinant ATIII protein was immunologically reactive with antisera raised against native human ATIII, formed stable complexes with thrombin, and was heparin-accelerated at the same concentration as native human ATIII. In addition, the recombinant ATIII retained specificity for the same molecular species of heparin that activates authentic human ATIII. This is the first successful production of active, recombinant ATIII in quantities that will allow purification on the milligram scale and permit a biochemical analysis of genetically engineered variants.
...
PMID:Expression of biologically active human antithrombin III by recombinant baculovirus in Spodoptera frugiperda cells. 199 47

The venom from Crotalus molossus nigrescens contains many activities including: hyde powder azure proteinase; N-benzoyl-arginine-ethyl-ester hydrolase; phospholipase; phosphodiesterase; desoxyribonuclease; fibrinogen coagulase; collagenase, fibrinolytic activity, and hemorrhagic factors. The venom, assayed with amounts of venom up to 50 micrograms protein per assay, does not contain acetylcholinesterase, phosphatase, amylase, ribonuclease, tyrosyl-ester hydrolase or hyaluronidase activities. The venom is lethal to mice with an i.p. LD50 of 2.35 mg/kg mouse. Fractionation of soluble venom by Sephadex G-75 separates at least five families of components. Fractions I-III contains all the enzymes, and fraction V have six small peptides. Further separation of fractions II-III on diethyl-amino-ethyl-cellulose columns at pH 8.0 and 8.3 gave pure proteinase E with a mol. wt of 21,390 and the following N-terminal amino acid sequence; Phe-Ala-Lys-Arg-Tyr-Val-Glx-Leu-Val-Ile-Val-Ala. A thrombin-like enzyme with a mol. wt of 75,000 was also purified from this venom by means of affinity and ion exchange chromatographies.
...
PMID:Characterization of the venom from Crotalus molossus nigrescens Gloyd (black tail rattlesnake): isolation of two proteases. 218 98

A new approach has been developed to circumvent the problems of false positive reactions in the Limulus Amoebocyte Lysate (LAL) assay for lipopolysaccharide (LPS) in root surface materials. These LAL-reactive materials include thrombin, thromboplastin, ribonuclease, ribonucleic acid, lipoteichoic acid and peptidoglycan fragments. In the present study, hot phenol/water extraction of these substances followed by ultracentrifugation of the resulting aqueous phases reduced their concentrations to very low levels. Furthermore, the application of Polymyxin B/Sepharose 4B affinity chromatography to these extracts enabled their intrinsic LAL-activity to be determined. Use of these techniques to assay root surface materials has identified LPS as being the major LAL-reactive material present. The mean LPS yield for the periodontally involved teeth was 4.13 micrograms/tooth, representing 2.82 micrograms/root. In contrast, the mean yield of LPS for the periodontally uninvolved teeth was 3.12 ng/tooth.
...
PMID:Identity of limulus amoebocyte lysate-active root surface materials from periodontally involved teeth. 346 18

Gabonase, an enzyme which acts on fibrinogen and factor XIII in uniquely thrombin-like ways, was purified to electrophoretic homogeneity from the venom of Bitis gabonica. On sodium dodecyl sulfate-polyacrylamide electrophoresis, the reduced protein behaved as a single chain with Mr = 30,600. The enzyme contains 20.6% carbohydrate, no free sulfhydryl groups and hence, from amino acid analysis, five disulfide bonds. Its extinction coefficient (E1%1cm) at 280 nm is 9.6. Its pI is 5.3. Gabonase has an active serine residue, is inactivated by phenylmethanesulfonyl fluoride, and has an active histidine which reacts with the chloromethyl ketone of tosyl-L-lysine. Its NH2-terminal amino acid sequence (Val-Val-Gly-Gly-Ala-Glu-Cys-Lys-Ile-Asp-Gly-His-Arg-Cys-Leu-Ala-Leu-Leu -Tyr-) is homologous to the B chain of thrombin. The activity of the enzyme is stabilized by calcium ion. It exhibits strong N alpha-p-tosyl-L-arginine methyl esterase activity, hydrolyzes tripeptide nitroanilide derivatives weakly or not at all, and cleaves no peptide bonds in insulin, glucagon, or the S peptide of ribonuclease. Gabonase clots fibrinogen with a specific activity of 45 NIH thrombin-equivalent units/mg, releasing both fibrinopeptides A and B and showing substrate inhibition at fibrinogen concentrations of 3 mg/ml or greater. The enzyme also activates factor XIII. It is not inactivated by either heparin or hirudin.
...
PMID:Thrombin-like enzyme from the venom of Bitis gabonica. Purification, properties, and coagulant actions. 352 80

Thrombin, via activation of vascular endothelial and smooth muscle cell thrombin receptors, modulates vascular wall healing. To understand the mechanisms that regulate human thrombin receptor (HTR) expression, we cloned and characterized the HTR gene. The HTR gene consists of Exon I, which contains the 5'-regulatory region and 85 nucleotides of coding sequence; a approximately 15-kb intron; and Exon II, which contains the remainder of the coding sequence and the entire 3'-untranslated region. Multiple transcription initiation sites were identified by S1 mapping and ribonuclease protection assay. DNA sequence analysis indicated the presence of two SP-1-AP-2 consensus binding sequences, near or within the transcription initiation sites, and consensus binding sequences for numerous regulatory proteins that potentially modulate HTR expression. Functional analysis of the HTR promoter was performed by transfecting human microvascular endothelial cells with HTR promoter region-luciferase constructs. The highest level of expression was obtained with a 0.7-kb promoter sequence and was progressively less with fragments of 0.54, 1.16, 1.6, and approximately3.2 kb. The data presented in this report provide a foundation for further characterization of the HTR gene and the mechanisms that regulate its expression within the blood vessel wall.
...
PMID:Cloning and identification of regulatory sequences of the human thrombin receptor gene. 882 85

Thrombin is one of the first regulatory molecules present at sites of CNS trauma or injury. Exposure of neuronal and glial cells to thrombin produces potent morphological as well as cytoprotective and cytotoxic effects, but little is known about how this important modulator affects neurotransmitter signaling. In astrocyte cultures that have been morphologically differentiated by exposure to transforming growth factor-alpha, addition of thrombin induced a retraction of astrocytic processes and suppressed the stimulation of phosphoinositide hydrolysis by the selective metabotropic glutamate receptor (mGluR) agonist 1-aminocyclopentane-1S,3R-dicarboxylic acid. In addition to the suppression of phosphoinositide hydrolysis, thrombin treatment produced a corresponding reduction in level of mGluR5 mRNA as demonstrated with ribonuclease protection assay and reduced content of mGluR5 receptor protein as seen with western blotting. In contrast, thrombin exposure up-regulated astrocyte beta-actin mRNA levels. A synthetic hexapeptide with a sequence corresponding to the amino-terminus of the thrombin receptor's tethered ligand also mimicked the ability of thrombin to suppress mGluR5 levels and to increase beta-actin mRNA content, suggesting that these effects of thrombin are mediated by proteolytically activated cell surface thrombin receptors. Thrombin's suppressive effect on mGluR5 was resistant to pretreatment with pertussis toxin or various protein kinase and protein phosphatase inhibitors. However, the serine/threonine protein kinase inhibitor H-7 did prevent thrombin-induced reversal of astrocyte stellation and induction of beta-actin mRNA levels, indicating that these effects of thrombin involve a signaling pathway distinct from the one that mediates the suppressive effects of thrombin on mGluR5.
...
PMID:Exposure of astrocytes to thrombin reduces levels of the metabotropic glutamate receptor mGluR5. 885 25

Protease nexin 1 (PN-1), a potent serpin-class antiprotease, is thought to be synthesized in the murine kidney. However, neither the cellular localization of PN-1 synthesis nor its role has yet been defined. To address these questions, we determined by in situ hybridizations RNase protection assay and immunoblotting, the sites of PN-1 mRNA accumulation in normal mouse kidneys and the modulation of PN-1 expression in several pathological conditions. In normal kidneys, PN-1 mRNA was detected primarily in glomeruli, most likely in mesangial cells. The glomerular expression of PN-1 was substantially enhanced not only in lupus-like glomerulonephritis (induced by IgG3 monoclonal rheumatoid factors or occurring spontaneously in lupus-prone mice), but also in mild glomerular lesions associated with intracapillary thrombi induced by IgG3 anti-trinitrophenyl monoclonal antibodies. In contrast, no modulation of PN-1 mRNA levels was observed during the course of lipopolysaccharide-induced acute tubular necrosis. A constitutive PN-1 gene expression and its up-regulation during glomerular injury suggest a possible role for PN-1 in glomerular biology. In view of its high inhibitory activity towards thrombin, mesangial PN-1 may be involved in the control of glomerular coagulation following initial glomerular injuries.
...
PMID:Protease nexin 1 in the murine kidney: glomerular localization and up-regulation in glomerulopathies. 894 77


1 2 3 Next >>

---