The 5'-terminal phosphates slow migration of single-stranded DNA fragments during electrophoresis in nondenaturing acrylamide gels.

Removal of the 5'-terminal phosphate results in an observable acceleration of the migration of single-stranded DNA fragments in the course of electrophoresis in nondenaturing acrylamide gels. This effect was observed with fragments 30-450 nucleotides in length. The relative difference in the migration of dephosphorylated and phosphorylated fragments depends on their length and primary structure and on the conditions of electrophoresis. The distinct mobility can advantageously be used to determine the level of terminal phosphorylation of DNA fragments during the work with phosphatases and polynucleotide kinases.