A comparison of a newly discovered invertebrate acid deoxyribonuclease with vertebrate deoxyribonuclease II
Russell, Anthony Post
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Characteristics of deoxyribonuclease II from calf thymus and spleen were described and verified by the following experimental procedures. Nuclei from calf thymus were prepared free of cytoplasm both by washing homogenized tissue in sucrose solutions, and by density gradient centrifugation in organic solvents. The action of the enzyme from nuclei and from a thymus homogenate was found to be similar when measured by light scattering and hyperchromic shift. Deoxyribonuclease II from calf spleen was purified by ammonium sulfate precipitation. Further purification of the enzyme on column chromatography resulted in fractions similar to those reported in the literature. The effect of sodium sulfate on the activity of splenic DNase II, purified by ammonium sulfate precipitation, was measured by the production of acid-soluble nucleotides from deoxyribonucleic acid during hydrolysis. The effect of the sulfate ion was also measured by viscometry, as was the effect of magnesium chloride, manganese chloride, sodium citrate and iodoacetic acid. The substances were all found to be inhibitory, which is in agreement with the results reported in the literature. Deoxyribonucleases active at an acid pH were extracted from representatives of four invertebrate phyla (Echinodermata, Mollusca, Arthropoda and Annelida) and compared with vertebrate deoxyribonuclease II with respect to ionic requirements and pH optima. [TRUNCATED]
Thesis (Ph.D)--Boston University
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