Crystalline Desoxyribonuclease

Kunitz, M.

doi:10.1085/jgp.33.4.363

Cited by 170 publications

(43 citation statements)

References 4 publications

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“…The presence of sucrose made almost no difference. The action of DNase on isolated nuclei and on DNP was tested in 0.14 M NaCl (rather than in sucrose); it was found that despite the presence of 3 mM MgCl2, enzyme activity was much reduced, as might have been expected, for Kunitz (15) had shown that in this concentration of NaCi, DNase activity is depressed by almost 50%. It is of interest to note that this effect of NaCl is reversible, for when nuclei were suspended in 0.14 M NaC1 and then returned to 0.25 M sucrose DNase had precisely the same effect on them as if they had remained in 0.25 M sucrose.…”

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confidence: 85%

The Structure of Chromatin

Mirsky

1971

Proc. Natl. Acad. Sci. U.S.A.

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The DNA in chromatin of isolated thymus nuclei, and in two different preparations of deoxyribonucleoprotein extracted from chromatin, has been digested with DNase. Chromatin is the term coined by Flemming to designate the material in the cell nucleus that takes basic stains. Flemming, on the basis of experiments by Zacharias, recognized that DNA is the substance in chromatin that takes basic stains (1). Kossel discovered histones and was aware that these basic proteins are combined with DNA in chromatin (2). Proteins other than histones are also combined with DNA in chromatin (3). Chromatin is a deoxyribonucleoprotein complex containing a large number of protein components and some RNA; the structure of this complex is not well understood. In the present study, the enzyme DNase is used to probe the structure of chromatin. Experiments are reported concerning the action of DNase on chromatin in isolated cell nuclei and on two different preparations of deoxyribonucleoprotein (DNP) extracted from nuclei. The action of DNase on preparations of DNP has been the subject of some recent investigations (4-6).Although DNP has been extracted from chromatin for 79 years, it was only about 10 years ago that some investigators began referring to the extracted material as chromatin (7). This practice seems reasonable, because the composition of the extracted DNP and some of its properties resemble those of chromatin in the nucleus. Even so, just how far this resemblance goes is not known, and it is unlikely that material as complex as chromatin is not significantly changed when extracted by any of the methods presently used. The likelihood of change is shown by the observations reported here on two preparations of DNP, both of which have been termed "chromatin" by different investigators, but which differ considerably from each other when treated with DNase. I would suggest that the term chromatin be reserved to designate the material in the cell nucleus for which Flemming first used the word, and that each DNP preparation have a subscript referring to those who devised the method by which that particular preparation was made. In this way we shall be reminded continually that the purpose of these investigations is to understand the chromatin of the cell nucleus-surely a highly significant material.Materials. Nuclei were isolated from calf thymus in a 0.25 M sucrose-mM CaCl2 medium (8). In some experiments nuclei were freshly prepared; in other experiments preparations stored at -60'C were used, for it was found that DNase acted on freshly prepared and on nuclei stored frozen in much the same way. DNP was prepared by two different methods. One preparation, beginning with thymus nuclei isolated in sucrose, was that recently described by Clark and Felsenfeld (6). It was stored at -60'C in 0.2 mM EDTA, pH 7.0, and was a clear solution at a concentration of 0.01 mg of DNA phosphorus per ml. It should be noted that this preparation of DNP, as are some others described in recent years, is similar to that described by Zubay an...

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confidence: 85%

The Structure of Chromatin

Mirsky

1971

Proc. Natl. Acad. Sci. U.S.A.

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“…DNAase I activity was measured by the hyperchromicity assay of Kunitz [13] with an Aminco DW2 spectrophotometer at 260 nm and 30 "C. The assay used contained 50 yg/ml salmon sperm DNA (grade 111) sodium salt, 1 mM MgC12, 0.1 mM CaC12 and 10 mM Tris-HC1 buffer, pH 8.0.…”

Section: Methodsmentioning

confidence: 99%

Isolation and Characterization of Secretory Actin . DNAase I Complex from Rat Pancreatic Juice

Rohr

Mannherz

1978

Eur J Biochem

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DNAase I isolated from rat pancreatic juice was always found in association with a protein of molecular weight 43000. This association leads to inhibition of the isolated rat pancreatic DNAase I activity by 66%. The molecular weight of the complex was found to be 74000 by gel filtration indicating a 1 : 1 molar association of both proteins. Since the protein of molecular weight 43000 has a number of properties similar to skeletal muscle actin such as filament formation, nucleotide binding, inhibition of the rat pancreatic DNAase I activity and comigration with skeletal muscle actin on polyacrylamide gels in the presence of dodecylsulfate, it is concluded that DNAase I is bound to actin in rat pancreatic juice in a 1 : 1 complex. It is demonstrated that a protein fraction from bile is able to activate the DNAase I enzymatic activity of the rat secretory actin ‐ DNAase I complex.

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“…These sections and duplicate sections not pretreated with alcohol were washed in 0.1 M NaCl for 20 minutes and then treated with a 1% solution of either crystalline bovine pancreas ribonuclease (Worthington Biochemical, Freehold, New Jersey) in 0.1 M acetate buffer, pH 5.0, or purified porcine spleen deoxyribonuclease (Worthington Biochemical) in 0.1 M acetate buffer, pH 4.6, for a period of 10 minutes to I hour (36,37). The sections were washed in several changes of phosphate buffered saline over a period of 25 minutes and were then incubated with serum from patient RM at room temperature for 20 minutes.…”

Section: Methodsmentioning

confidence: 99%

Localization of C‐reactive protein in synovium of patients with rheumatoid arthritis

Gitlin

1977

Arthritis & Rheumatism

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Synovial biopsies from 8 patients with rheumatoid arthritis, 2 patients with degenerative osteoarthritis, and 4 patients with nonarthritic disease were studied for localization of C-reactive protein (CRP) using immunofluorescence microscopy. The nuclei of many synoviocytes and histiocytes in rheumatoid synovial membrane were found to bind CRP. Cultures of rheumatoid synovium in 14C-labeled amino acids produced radioactive IgG, IgM, IgA, and C3, but not CRP, indicating the synovial-bound CRP was not of local origin. A few CRP-binding nuclei were present in one osteoarthritic synovium, but none was found in the other and none in synovium from the 4 nonarthritic patients. The nature of the nuclear CRP ligand in rheumatoid synovium was not determined.C-reactive protein (CRP) is a normal constituent of human plasma (1). It is synthesized by all normal individuals, and its average concentration ranges from

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Crystalline Desoxyribonuclease

Cited by 170 publications

References 4 publications

The Structure of Chromatin

The Structure of Chromatin

Isolation and Characterization of Secretory Actin . DNAase I Complex from Rat Pancreatic Juice

Localization of C‐reactive protein in synovium of patients with rheumatoid arthritis

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