Efficient purification of DNA fragments using a protein binding membrane

A novel and efficient method has been developed for isolation of correctly digested DNA fragments without the use of classic size-dependent electro- phoretic separation methods. To achieve this, DNA fragments are end-labelled by haptens. After specific endonuclease digestion of the hapten-labelled DNA, the DNA is incubated with a protein that specifically binds to the hapten. The incubation mixture is then passed through a cartridge containing a protein- binding membrane that does not bind DNA. Undigested and partly digested DNA are retained on the membrane, while correctly digested DNA is selectively recovered for use in further downstream applications.