[Determination of the activity of a polynucleotide phosphorylase preparation from E. coli]

Thin-layer chromatography was employed to measure the activity of polynucleotide phosphorylase (PNP-ase) from E. coli during purification and in the resultant preparation. The TLC data were verified with respect to released inorganic orthophosphate and to 14C-AMP incorporation rate. It is concluded that TLC can be used to determine PNP-ase activity in crude extract, at various purification stages and in the final preparation, yielding correct results.