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Results for “DESOXYRIBONUCLEASE”

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At least 19 recordsLinked to original sources
PubMed1950

Crystalline desoxyribonuclease; isolation and general properties; spectrophotometric method for the measurement of desoxyribonuclease activity.

A crystalline enzyme capable of digesting thymus nucleic acid (desoxyribonucleic acid) has been isolated from fresh beef pancreas. The enzyme called "desoxyribonuclease" is a protein of the albumin type. Its molecular weight is about 60,000 and its isoelectric point is near pH 5.0. It contains about 8 per cent tyrosine and 2 per cent tryptophane. It is readily denatured by heat. The denaturation is reversible if heated in dilute acid at pH about 3.0. The digestion of thymus nucleic acid by crystalline desoxyribonuclease is accompanied by a gradual increase in the specific absorption of ultraviolet light by the acid. The spectrophotometric measurement of the rate of increase in the light absorption can be conveniently used as a general method for estimating desoxyribonuclease activity. Details are given of the method for isolation of crystalline desoxyribonuclease and of the spectrophotometric procedure for the measurement of desoxyribonuclease activity.

Animals↗
PubMed1951

Elaboration of desoxyribonuclease by streptococci in the resting state and inhibition of the enzyme by a substance extractable from the cocci.

As a preliminary to the study of desoxyribonuclease elaboration by resting cells, 34 strains of streptococci were examined for their capacity to produce desoxyribonuclease in broth cultures. The largest amounts of enzyme were found to be produced by strains belonging to Lancefield group A and by certain strains belonging to groups C and D. Many strains, especially those belonging to other groups, produced little or no enzyme. Washed cocci of certain strains elaborated desoxyribonuclease extracellularly upon suspending them in a solution containing an energy source, phosphate and magnesium ions. When any one of these factors was omitted, no enzyme was produced. The appearance of extracellular desoxyribonuclease was found to be inhibited by a variety of enzyme poisons, and this and other findings indicate that desoxyribonuclease is synthesized in the resting cell system. Cocci were found to contain a substance which partially inhibits the desoxyribonuclease formed by group A strains but which fails to inhibit the desoxyribonuclease formed by strains belonging to groups B and C or to inhibit the desoxyribonuclease derived from yeast, barley, and pancreas. The inhibitor of group A desoxyribonuclease has been identified as streptococcal ribonucleic acid. Preparations of ribonucleic acid derived from yeast differed from streptococcal ribonucleic acid in failing to inhibit the group A desoxyribonuclease.

Bacteria↗
PubMed1950

Crystalline desoxyribonuclease; digestion of thymus nucleic acid; the kinetics of the reaction.

A study was made of the enzymatic properties of crystalline desoxyribonuclease. The general effect of the crystalline enzyme on its specific substrate, thymus nucleic acid, was found to be essentially the same as described by previous workers for the digestive action of crude preparations of the enzyme. The digestive action consists mainly in splitting thymus nucleic acid into fragments approaching the size of tetranucleotides. The digested nucleic acid is diffusible through collodion or cellophane membranes and is non-precipitable with strong acid, alcohol, or proteins. The digestion of thymus nucleic acid by desoxyribonuclease is accompanied by the liberation of one atom equivalent of free acid per four atoms of nucleic acid phosphorus. Crystalline desoxyribonuclease acts very slowly, if at all, in the absence of magnesium (or manganese) ions. The optimal concentration of magnesium ion required increases with the increase in concentration of the substrate but is independent of the enzyme concentration. The optimal pH range for the action of crystalline desoxyribonuclease is 6.0 to 7.0. A study was made of the kinetics of the digestion of thymus nucleic acid as manifested mainly by the gradual formation of acid-soluble split products. At low concentrations of nucleic acid, the process approximates closely a reaction of the first order, the unimolecular constant being independent of the concentration of desoxyribonuclease in the digestion mixture. At relatively higher concentrations of substrate, however, the initial rate of reaction decreases rapidly with the increase in concentration of substrate, and the reaction as a whole is represented by non-symmetric S-shaped curves apparently too complicated for a simple rational interpretation.

Deoxyribonucleases↗
PubMed1949

The inhibition of streptococcal desoxyribonuclease by rabbit and human antisera.

Rabbit antisera against partially purified streptococcal desoxyribonuclease inhibit the action of the enzyme on its substrate. The activity of pancreatic desoxyribonuclease is not affected by these antisera. Similarly antibody against pancreatic nuclease does not inhibit the streptococcal enzyme. Certain patients develop inhibitory antibody to streptococcal desoxyribonuclease following streptococcal infections, occasionally in very high titer, although the proportion of patients showing an antibody response appears to be lower than in the case of streptokinase and streptolysin O. The pattern of antibody response to desoxyribonuclease has been compared to that of streptokinase and streptolysin O in a group of ninety patients from an epidemic of scarlet fever.

Animals↗
PubMed1952

Some aspects of the desoxyribonuclease activities of animal tissues.

It has been found that many animal tissues contain "acid" desoxyribonucleases with pH optima near 5.2. A chemical method for the determination of this activity is described. The pancreatic desoxyribonuclease crystallized by Kunitz and shown to have a neutral pH optimum occurs in the pancreas together with the "acid" enzyme, but only the "neutral" enzyme occurs in the pancreatic juice. The ratio of "neutral" to "acid" DNAase activities in the pancreas is greater than 200, but in all other tissues examined there is no appreciable concentration of the neutral enzyme. It is concluded that neutral DNAase, like trypsin or lipase, has a digestive function. Some problems in the activation of the secretory enzyme in neutral pancreatic extracts are described. This activation can be interpreted in terms of a specific inhibitor or an inactive form of the enzyme. A comparison of the "acid" DNAase activities of different organs of the calf, horse, chicken, mouse, and rat indicates a possible connection between the DNAase concentration of a tissue and its capacity for proliferation or regeneration. However, the comparative DNAase activities of fetal and adult tissues do not support the view that DNAase function is limited to some simple role in the mechanics of cell division. Studies on the incorporation of glycine-N(15) into the desoxypentose nucleic acids of avian red cells, and mouse liver, pancreas, and kidney show that the N(15) uptake into the DNA of the chromosome is most rapid in tissues with high DNAase concentrations. No N(15) incorporation is observed in the DNA of avian red cells, which have negligible concentrations of the enzyme. The analyses of tissues and nuclei isolated in non-aqueous media show that the bulk of the enzyme occurs in the cytoplasm of the cell, and that nuclear concentrations vary from tissue to tissue. A theory relating the DNAase activity of the cell to its over-all desoxypentose nucleotide metabolism is discussed. No evidence has been found for the presence of inhibitors of the "acid" DNAase in animal tissues.

Animals↗
PubMed1956

Concentration of acid phosphatase, ribonuclease, desoxyribonuclease, beta-glucuronidase, and cathepsin in droplets isolated from the kidney cells of normal rats.

1. Three fractions of "droplets" having diameters of 1 to 5 micro (fraction I), 0.5 to 1.5 micro (fraction II), and 0.1 to 1.0 micro (fraction III) were isolated from the kidney cells of normal rats. 2. All three "droplet" fractions showed 10 to 15 times higher activities of acid phosphatase, beta-glucuronidase, ribonuclease, desoxyribonuclease, and cathepsin than the total homogenate and the mitochondrial fraction. 3. After a rough fractionation of the total homogenate, approximately 50 per cent of the 5 enzymes was found in the fractions which contained the "droplets" and approximately 30 per cent in the supernatant fluid. 4. The similarities between the enzymatic properties of the "droplets" from kidney cells and of the fractions isolated from liver cells by other investigators have been discussed.

Acid Phosphatase↗
PubMed1987

Identification of an Epstein-Barr virus-specific desoxyribonuclease gene using complementary DNA.

We have recently obtained 18 distinct cDNA clones representing different genes expressed in the early phase of EBV infection. One of them, c37, which is situated at the position 12907-122451 in the B95-8 viral genome, is shown here to code for a viral desoxyribonuclease [DNase]. Cell free translation of c37-selected messenger RNA yielded a protein of about 52 KDa which was immunoprecipitated by a high EA titer serum from nasopharyngeal carcinoma patient. This protein showed a DNase activity which was resistant to high salt concentrations (150 to 300 mM KCl) and was specifically neutralized by EA positive serum. These properties are typical of the EBV-specific DNase activity that we recently described in chemically induced EBV-transformed lymphoid cells. The same results were obtained on cell-free translation of the native RNA synthesized in vitro from pGEM-37 plasmid containing the entire c37 cDNA sequence (1.53 Kb). These data indicate that the BGLF5 open reading frame contained in c37 encodes for the EBV-specific DNase.

Base Sequence↗
PubMed2003

Lupus and desoxyribonuclease.

The dominant autoantigen in SLE is the nucleosome and immune complexes involving nucleosomes are the major cause of tissue damage. Nucleosomes can be broken down in vivo with Desoxyribonuclease 1. DNase 1 from humans and mice is inhibited by actin and it is proposed that the release of platelet actin at inflammatory sites is one mechanism which causes nucleosomes to become antigenic. Rats whose DNase 1 is not inhibited by actin do not get lupus. Treatment of NZB/W mice with recombinant DNase slows the onset of their disease if given early and improves the renal disease if given later. This disease can also be entirely prevented by treatment with dexamethasone. Mice whose DNase 1 gene is knocked out are known to develop lupus and to be otherwise normal. DNase 1 especially in its mutant actin and salt resistant forms remains an attractive candidate for the treatment of SLE.

Deoxyribonucleases↗
PubMed1975

[Desoxyribonuclease and lecithinase activity in antibiotic-resistant and -sensitive staphylococci].

Staphylococcus aureus, a laboratory strain 209-P and strain I isolated freshly from infected wounds, as well as lincomycin hydrochloride, ampicillin, oxacillin and methicillin manufactured in the USSR and cephaloridin manufactured by "PLIVA" in Yugoslavia were used. Various activity levels of desoxyribonuclease and lecitinase of the staphylococci depending on sensitivity or resistance of the test-microbe to the antibiotics were shown. The activity of the above microbial enzymes characterizing the pathogenic properties decreased with development of the antibiotic resistance, sometimes to complete inactivation of the enzymes synthesized by the staphylococci. In spite of closeness of their modes of action the semisynthetic penicillins had a differentiating effect on the above enzymes.

Anti-Bacterial Agents↗
PubMed1981

Dissociation of suction blister roof epidermis with trypsin and desoxyribonuclease into viable single cells.

Human epidermis, obtained in vivo by the suction blister method, was dissociated with trypsin and desoxyribonuclease into a single-cell suspension. Autoradiographic analysis of the blister roof epidermis and of the epidermal cell suspension was performed to show that neither the suction procedure nor the enzymatic dissociation affected DNA synthesis of the epidermal cells.

Adult↗