The Protein and DNA Removal Columns are designed to separate small molecules and liposomes from proteins, DNA and RNAs. The columns can be used for preparation of samples by removing the DNA, RNA or proteins from biological samples for HPLC or other applications. They can be also used for separation of free drugs and liposome-encapsulated drugs from protein-bound or DNA-bound drugs and separation of free ligands from receptor-bound ligands. Binding between the biological molecules and the column resin is mainly charge-charge interactions. The proteins, nucleic acids and protein-bound drug stay on the column while the small polar molecules or liposomes are in the elute. Organic and inorganic phosphate molecules may also bind to the column. The binding capacity of the spin columns is more than 100 µg of protein or 20 µg of DNA per column.
The Protein and DNA Removal Spin-columns (Catalog number: PNR020) includes 20 pre-packed spin-columns in 50 % ethanol..
PROTOCOLS
1. Spin the pre-packed columns briefly using a bench-top microcentrifuge to set down the resin. Cut off the caps of 1.5 ml-eppendorf tubes and use the tubes as receivers of the spin columns. Remove the column bottom tips and caps. Place the columns into the1.5 ml-eppendorf tubes and spin the columns at 13,000 rpm for 1 min. Discard the solution. Load 200 µl of water and spin the columns at 13,000 rpm for 1 min. Discard the solution. Transfer each column into a clean labeled 1.5-ml eppendorf tube.
2. Load 200 µl of the sample in a buffer containing 100 mM NaCl onto each column and spin the columns at 1000 rpm for 1 min. Then continue to spin the columns at 13,000 rpm for 1 min and save the elute.
Note: Step 2 can be repeated if the sample volume is more than 200 µl until the column binding capacity is reached. Inclusion of 100 mM NaCl is not necessary for removal of protein or DNA but helps to minimize binding of small charged molecules on the column.
3. Centrifuged the elute at 13,000 rpm for 1 min to remove any insoluble material. Alternatively, the elute can be filtrated with a 0.22 µm to remove any insoluble material.