Pure genomic DNA from bacteria

(from QIAGEN genomic DNA Handbook )

Principle: DNA binding and washing on QIAGEN genomic-tips The cleared lysate is loaded onto a pre-equilibrated QIAGEN genomic-tip by gravity flow.The salt and PH conditions of the lysate and the superior selectivity of the QIAGEN resin ensure that only DNA binds,while degraded RNA,cellular proteins,and metabolites are not retained and appear in the flow-through fraction. The QIAGEN genomic-tip is then washed with a medium-salt buffer(Buffer QC).This buffer completely removes any remaining contaminants,such as traces of RNA and protein,without affecting the binding of the DNA.Buffer QC also disrupts nonspecific interactions and allows removal of nucleic acid-binding proteins without the use of phenol.The low concentration of ethanol in the wash buffer eliminates nonspecific hydrophobic interactions,futher enhancing the purity of the bound DNA.The DNA is then efficiently eluted from the QIAGEN Genomic-tip with a high-salt buffer(QF).