Webb Ziesenheim Bruening Logsdon Orkin & Hanson, P.C.
Method for isolating DNA from biological cells
 This invention relates to a method for isolating DNA from biological cells containing protamines. The biological parent material is decomposed using salts with low molecular weight above a critical ionic strength cleaving all ionic bonds between DNA and protamines and polystyrene sulfonic acid (PSA) and/or its derivatives in combination with sodium lauryl sulfate. These substances, together with protamines at pH values ranging from 7.5 to 8.5, form insoluble polyelectrolyte complexes facilitating the release of DNA from its natural complexes which can then be precipitated using ethanol. The method according to the invention is fundamentally different from conventional methods as it uses neither enzymes nor toxic extracting agents such as chloroform or phenol. The method according to the invention is very efficient and non-polluting; it can be carried out easily and yields products with a high degree of purity. As the treatment is very gentle, this method is suitable to purify DNA of very high molecular weight. 
C
C12N
inventional
Trinh Cam
Khon