PCR amplification products are of limited use for the study of DNA/protein interaction.

Conventional methods for labeling double-stranded DNA lead to high specific activity. Yet they often alter the target DNA sequence to such an extent as to prevent a meaningful protein/DNA interaction analysis. Therefore we tried to establish a polymerase chain reaction (PCR)-based method which allows radiolabeling to high specific activity and should maintain the protein binding capability of small double stranded DNA fragments. By using PCR it is possible to label double stranded DNA to high specificity, but the protein binding capability of such DNA is drastically reduced.