title: Size fractionation of double-stranded DNA by precipitation with polyethylene glycol.
abstract: We show that DNA molecules of differing molecular mass are separable by selective precipitation with polyethylene glycol (PEG+.. Higher molecular mass DNA precipitates at lower PEG concentrations than lower molecular mass DNA. Double-stranded DNA can be fractionated at least in the range of 3 times 10-7 to 1 times 10-5 daltons. The effects on PEG concentration, sodium chloride concentration, DNA concentration, pH, divalent ions, precipitation time, and centrifugal force have been determined. These studies show PEG precipitation offers a size fractionation method for DNA which is convenient, of high capacity, and applicable over a wide range of conditions. However, resolution is not high and separation of two species approaches 100% only if they differ in molecular mass by at least a factor of two.
mesh_terms: D002413:Cations, Divalent; D003090:Coliphages / Q000032:analysis*; D004267:DNA Viruses / Q000032:analysis; D004279:DNA, Viral / Q000302:isolation & purification; D003851:Deoxyribonucleases; D004591:Electrophoresis, Polyacrylamide Gel; D004720:Endonucleases; D006193:Haemophilus influenzae / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D008722:Methods; D008970:Molecular Weight; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D013997:Time Factors; D014461:Ultracentrifugation
chemical_list: D002413:Cations, Divalent; D004279:DNA, Viral; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D003851:Deoxyribonucleases; D004720:Endonucleases