In the isolation of genomic DNA by silica gel membrane column method why only nucleic acids bound to the silica gel ,Can u tell me why not amino acids attach to the silica gel membrane ?
It is not silica but silica-coated glass beads. Glass has the property to bind DNA reversibly in the presence of high salt. Therefore, elution of bound DNAis carried out by water or buffer without salt. It is physical interaction involving weak forces between DNA and glass particles..
The polyanionic DNA backbone binds to the positively charged silica beads. This depends on use of the appropriate buffer, of course. Some negatively charged proteins may bind under the right buffer conditions.