Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence of a nuclear DNA polymerase in mouse sperm from adult testes has been confirmed and the properties of this enzyme further investigated. This activity was shown to be greatly enhanced by treating the spermatozoa with methanol or ethanol before incubation in the reaction medium or by their addition in small amounts to this medium. It was protected against degradation by nuclear proteases by adding soybean trypsin inhibitor and was stimulated by ATP. It was found to be Mg2+ dependent (optimum concentration: 7.5 mM), DNA dependent, and all four deoxynucleoside triphosphates were needed for optimal reaction. The radioactive acid-precipitable product of polymerization was not eliminated by organic solvents, nor by pronase, ribonuclease or by nuclease S1; however, it was converted to a large extent to acid-soluble products by pancreatic deoxyribonuclease. Since it was only partially solubilized by Triton X-100, it therefore did not appear to be preferentially associated with the nuclear membranes. The activity recovered after incubation depended also on the pH (optimum at pH 8.3) and did not work well in a medium for DNA polymerase alpha. The temperature for maximum incorporation of nucleotides was found to be 32 degrees C and, under our conditions, the reaction was linear for 30 min. The DNA polymerase activity was inhibited by low and high concentrations of KCl. It was not lowered by N-ethylmaleimide or p-hydroxymercuribenzoate; urea slightly stimulated the reaction and this stimulation was reversed by subsequent treatment with N-ethylmaleimide. Actinomycin D (40 mug/ml), ethidium bromide (25--50 muM), netropsin (5--50 mug/ml), and spermidine (0.5--2.5 mM) lowered the polymerization of DNA precursors. The nuclear enzyme could shift from the endogenous template to activated exogenous calf thymus DNA, the resulting nuclear radioactivity being reduced. The endogenous DNP template ability was not increased by deoxyribonuclease activation according to the method of Aposhian and Kornberg (J. Biol. Chem. (1962) 237, 519--525) suggesting that the amount of DNA polymerase associated with chromatin was probably limiting the reaction. The DNA polymerase activity detected in mouse sperm nuclei has numerous properties of low molecular weight DNA polymerases (DNA polymerase beta) reported in several eukaryotic organisms.
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PMID:Further characterization of a DNA polymerase activity in mouse sperm nuclei. 1 3

Agarose-poly-L-lysine (Ag-(lys)n-DNA) has been used to bind DNA for assay of anti-DNA antibodies (ab). In this work, an algorithmic approach has been used to classify antinuclear ab (ANA) as being directed against native DNA (dsDNA), denatured DNA (ssDNA), DNA-protein complexes (deoxyribonucleoprotein; DNP), and against antigens which are independent of DNA (iDNA). These ab were subjected to Ag-(lys)n-DNA, and the selectivity of this adsorbent for the various specificities of ab was determined. The DNA on the columns was left untreated or treated with S1 nuclease, this being effected either by treating the DNA prior to introducing it onto the columns or by adding S1 nuclease to the columns after the DNA was bound. Ag-(lys)n-DNA adsorbs ab directed against ssDNA and DNP as well as ab to dsDNA; iDNA ab are not adsorbed. S1 nuclease treatment does not effectively remove ssDNA regions from the Ag-(lys)n-DNA, but it does result in the abolition of the adsorption of a population of ab which are in the anti-DNP sera and contribute to the total ANA load. While anti-iDNA ab are not adsorbed onto the columns, they do contribute to the ANA titer, unlike anti-ssDNA ab which are adsorbed onto the Ag-(lys)n-DNA but do not contribute to the ANA titer. We conclude that Ag-(lys)n-DNA bears antigenic sites for dsDNA, ssDNA, and DNP ab and suggest that our understanding of the characteristic ab-binding profile of this versatile immunoadsorbent may have applications in the study of autoimmune diseases.
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PMID:Characteristics of antibodies adsorbed on the DNA immunoadsorbent, agarose poly-L-lysine-DNA. 244 98