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:3.1.21.1 (DNase)
7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence is presented for a direct interaction of the intrinsic membrane protein 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) purified from avian smooth muscle (chicken gizzard) and the cytoskeletal component actin. Two different modes of interaction can be discerned: firstly, an immediate inhibitory effect of preferentially filamentous actin (F-actin) on the enzymic (i.e., AMPase) activity of 5'-nucleotidase and a direct binding of this enzyme to immobilized F-actin. Since these effects are suppressed by the addition of myosin subfragment 1, binding of 5'-nucleotidase appears to occur along the F-actin filament axis. Secondly, a time- and 5'-nucleotidase concentration-dependent transformation of also preferentially F-actin into a form unable to inhibit the enzymic activity of deoxyribonuclease I (DNAase I). This desensitization of actin versus DNAase I is not due to a denaturation process and was found to be reversible after addition of ATP. Furthermore, it does not seem to effect the ability of actin to bind to DNAase I. The transformation is accompanied by the hydrolysis of actin-bound nucleotide into adenosine, which remains bound to actin. Therefore, the desensitization of actin versus DNAase I appears to be due to a nucleotide-dependent conformational change of actin. An unidentified contamination of the 5'-nucleotidase preparations to a varying degree with ADPase and ATPase activities appears to be responsible for the desensitization process, although a synergistic role of these activities and 5'-nucleotidase cannot be excluded.
...
PMID:The interaction of 5'-nucleotidase purified from chicken gizzard and actin, and the reversible loss of the inhibitory capacity of actin on deoxyribonuclease I. 298

Mycoplasmalike organisms (MLOs), purified from aster yellows-infected plants were osmotically lysed, and the membranes were separated from the cytoplasmic fraction through differential centrifugation. Electron microscopic examinations of sections of the purified MLOs and the isolated membranes showed pleomorphic bodies and unit membranous empty vesicles, respectively. Cell fractions were tested for NADH oxidase, NADPH oxidase, ATPase, RNase, DNase, and p-nitrophenyl phosphatase activity. NADH oxidase and ATPase were confined to the membrane fraction and NADPH oxidase to the cytoplasmic fraction of the MLOs. para-Nitrophenyl phosphatase, RNase, and DNase activities were detected in both membrane and cytoplasmic fractions, but p-nitrophenyl phosphatase and RNase appeared to be associated with membranes and DNase with the cytoplasmic fraction. Glucose-6-phosphate dehydrogenase was found in the cytoplasmic fraction of the MLO cells. Our findings on the distribution of enzymes in MLO cells and cell fractions are the first basic documentation on nonhelical, nonculturable microbes parasitic to plants.
...
PMID:Enzymatic activities in cell fractions of mycoplasmalike organisms purified from aster yellows-infected plants. 299 32

The transmembrane topography of the rat hepatocyte ectoenzyme 5'-nucleotidase was studied by the use of glycoprotein labelling and limited-proteolysis techniques. Comparison, by one-dimensional peptide mapping, of enzyme iodinated from outside the cell with that iodinated in the solubilized state showed that no additional iodination sites were revealed on solubilization. Incubation of newly synthesized enzyme in a microsomal membrane fraction with proteinase showed that the entire molecule of 5'-nucleotidase was protected from proteolysis. These data suggest that little, if any, of the 5'-nucleotidase molecule is present on the cytoplasmic side of the plasma membrane. No evidence was found for a previously proposed interaction between 5'-nucleotidase and actin, although the ability of preparations of 5'-nucleotidase to prevent inhibition of deoxyribonuclease I by actin was explained by minute traces of ATPase activity. Comparison of peptide maps of enzyme labelled by iodination or by methods specific for carbohydrate showed that in both cases predominantly one section of the molecule was labelled. It is proposed that the enzyme is a short-stalked integral membrane protein without a cytoplasmic domain in which about one-third of the molecule forms the accessible molecular surface.
...
PMID:The membrane topography of ecto-5'-nucleotidase in rat hepatocytes. 301 17

A high-molecular-weight protein complex that is capable of accurate transcription initiation and termination of vaccinia virus early genes without additional factors was demonstrated. The complex was solubilized by disruption of purified virions, freed of DNA by passage through a DEAE-cellulose column, and isolated by glycerol gradient sedimentation. All detectable RNA polymerase activity was associated with the transcription complex, whereas the majority of enzymes released from virus cores including mRNA (nucleoside-2'-O)methyltransferase, poly(A) polymerase, topoisomerase, nucleoside triphosphate phosphohydrolase II, protein kinase, and single-strand DNase sedimented more slowly. Activities corresponding to two enzymes, mRNA guanylyltransferase (capping enzyme) and nucleoside triphosphate phosphohydrolase I (DNA-dependent ATPase), partially sedimented with the complex. Silver-stained polyacrylamide gels, immunoblots, and autoradiographs confirmed the presence of subunits of vaccinia virus RNA polymerase, mRNA guanylyltransferase, and nucleoside triphosphate phosphohydrolase I, as well as additional unidentified polypeptides, in fractions with transcriptase activity. A possible role for the DNA-dependent ATPase was suggested by studies with ATP analogs with gamma-S or nonhydrolyzable beta-gamma-phosphodiester bonds. These analogs were used by vaccinia virus RNA polymerase to nonspecifically transcribe single-stranded DNA templates but did not support accurate transcription of early genes by the complex. Transcription also was sensitive to high concentrations of novobiocin; however, this effect could be attributed to inhibition of RNA polymerase or ATPase activities rather than topoisomerase.
...
PMID:Sedimentation of an RNA polymerase complex from vaccinia virus that specifically initiates and terminates transcription. 303 83

The Escherichia coli RecB protein, normally synthesized in low amounts, has been amplified by linkage of the recB gene to the phage lambda leftward promoter in an expression plasmid. From strains harboring this plasmid, RecB protein has been purified to homogeneity by a simple procedure which includes affinity chromatography on a column of RecC protein bound to agarose. The purified RecB protein has DNA-dependent ATPase activity but no exonuclease activity. RecC protein alone has neither ATPase nor exonuclease activity. However, when combined together, the RecB and RecC proteins show the ATP-dependent double-stranded exonuclease properties characteristic of the RecBC DNase.
...
PMID:Reconstitution of RecBC DNase activity from purified Escherichia coli RecB and RecC proteins. 315 26

The histochemistry and ultrastructure (SEM and TEM) of the spermatheca of Biomphalaria glabrata was investigated to elucidate the function of this organ and to compare its structure and function to similar organs found in other species. The spermatheca has a debris-filled lumen surrounded by a thin wall of tissue. The cells adjacent to the lumen are of three columnar epithelial cell types. Two cell types have abundant microvilli and mammalian cell-like organelle distribution and morphology. The above cell types differ in the electron density of their cytoplasms, nuclear morphologies, and organelle content. The third cell type differs from the other two in its cytoplasmic makeup. However, the most distinctive difference is the presence of large numbers of cilia at the apical surface with no evidence of microvilli. These columnar cells rest on a basal lamina adjacent to a two to three cell thick muscle layer. The entire organ is surrounded by an adventitia of unusual morphology. Histochemical investigation demonstrated that DNAase, RNAase, and protease are present in the lumen, alkaline phosphatase is associated primarily with the microvilli, small amounts of acid phosphatase are concentrated in the midcell area of the columnar epithelium, and ATPase activity is localized in the muscle cells and just below the absorptive surface of the microvillous cells. The luminal contents and adventitial areas are Sudan Black B positive, all areas of the lumen and organ wall are PAS positive, the cell nuclei and amorphous masses in the lumen showed Feulgen staining, and large vesicles in the columnar cells were Oil Red O positive. Apparently, the spermatheca of B. glabrata is both a digestive and absorptive structure. Although this organ shares functional similarities with those found in opisthobranchs and terrestrial pulmonates, the epithelia of the spermatheca differ dramatically in these groups.
...
PMID:Structure and function of the spermatheca in a snail host of schistosomiasis, Biomphalaria glabrata. 364 39

An ATPase activity that is completely dependent on DNA is associated with the ATP-dependent DNase (recB-recC enzyme) purified from Escherichia coli. There is a strong correlation between the ATPase and the DNase activities under various assay conditions. With E. coli DNA as substrate, 8-9 molecules of ATP are hydrolyzed to ADP and inorganic phosphate for every phosphodiester bond hydrolyzed by the DNase. The possible functional relationship of the ATPase and DNase activities is discussed.
...
PMID:Adenosine triphosphatase associated with adenosine triphosphate-dependent deoxyribonuclease (recB-recC enzyme-E. coli-ATP to phosphodiester hydrolysis ratio-DNA-dependent ATPase activity). 425 17

Exonucleolytic cleavage of DNA by the recBC DNase is accompained by a DNA-dependent ATP hydrolysis that ceases when the DNA that has been digested to a limit. On the other hand, DNA that has been crosslinked by 4,5',8-trimethylpsoralen in the presence of 360-nm light remains an effective cofactor in the ATPase reaction, but is resistant to digestion by the enzyme. Psoralentreated DNA is degraded by pancreatic DNase, micrococcal nuclease, and Escherichia coli B restriction enzyme, but not by Neurospora crassa nuclease, suggesting that crosslinking did not grossly distort the duplex structure of the DNA. The psoralen-DNA is not a potent inhibitor, but competes with single-stranded DNA from bacteriophage fd for the recBC DNase to roughly the same extent as does normal duplex DNA. DNA treated with psoralen in the dark, exposed to 360-nm light in the absence of psoralen, or treated with the intercalating agents ethidium bromide, 9-aminoacridine, ICR-191, or actinomycin D, responds to the enzyme no differently from untreated DNA. However, DNA crosslinked with mitomycin C or nitrogen mustard behaves similarly to psoralen-treated DNA. The relationship of these findings to models for the function and control of the recBC ATPase and nuclease, and the advantages of psoralen as a DNA crosslinking agent, are discussed.
...
PMID:Uncoupling of the recBC ATPase from DNase by DNA crosslinked with psoralen. 426 6

Previous experiments have indicated that the gam gene of bacteriophage lambda is responsible for an inhibition of the RecBC DNase-an enzyme that is essential for the major host pathway of genetic recombination. We report here experiments that define the inhibitor as the protein product of the gam gene ("gamma-protein") and that characterize the inhibition reaction with highly purified preparations of gamma-protein and RecBC DNase. Genetic characterization was performed with partially purified fractions prepared from cells infected with various lambda mutants. An activity that inhibits RecBC DNase was absent in extracts prepared after infection by phage that carry nonsense or deletion mutations in the gam gene; this activity was highly thermolabile in an extract prepared after infection by phage that carry a temperature-sensitive mutation in the gam gene. For biochemical characterization, the gamma-protein has been purified more than 800-fold. This highly purified preparation inhibited all of the known catalytic activities associated with the RecBC enzyme, but exhibited no detectable DNase or ATPase activities by itself. These findings are discussed in terms of their implications for regulation of genetic recombination and bacteriophage lambda development.
...
PMID:Purification and properties of the gamma-protein specified by bacteriophage lambda: an inhibitor of the host RecBC recombination enzyme. 427 17

After dissociation of the E. coli recBc DNase (ATP-dependent DNase) with concentrated NaCl, two subunit proteins were isolated by ion exchange chromatography. Combination and subsequent incubation of the subunits resulted in the appearance of the original DNase. The subunit proteins, designated alpha and beta, have s(20,omega) of 4.1 S and 8.1 S, respectively. The alpha subunit possesses neither the ATP-dependent Dnase nor the DNA-dependent ATPase of the original enzyme. The beta subunit contains a low level of both enzymatic activities in a ratio markedly different from that of the original enzyme. The beta subunit complemented extracts from both recB and recC mutant strains to produce recBC DNase, while the alpha subunit did not complement either extract. These results suggest that recB and recC genes are both required for the production of beta subunit and that the recBC DNase molecule contains a protein component (alpha) that is not determined by either the recB or the recC gene.
...
PMID:The recBC deoxyribonuclease of Escherichia coli: isolation and characterization of the subunit proteins and reconstitution of the enzyme. 428 72


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---