Isolation of a polynucleotide phosphorylase mutant using a kanamycin resistant determinant

Insertion in an episome of a kanamycine-resistant element (Tn5) at the polynucleotide phosphorylase gene level, results, after transduction into a wild strain, by the loss of activities specific to polynucleotide phosphorylase. A low phosphorolytic activity is nevertheless detectable in crude extracts, but no longer in extracts slightly purified after heat treatment at 54 degrees C. The part played by other enzymes in these activities is discussed. Bacterial growth is not affected by introduction of the mutation.