TLC analysis of PPK enzymatic activity product. Lanes: 1, P. aeruginosa PPK reaction mixture; 2, polyP purified with Glassmilk from the reaction mixture shown in lane 1; 3, P. aeruginosa polyP digested with rPPX1; 4, purified polyP synthesized by E. coli PPK; 5, E. coli polyP digested with rPPX1; 6, reaction mixture in lane 1 digested with an M. bovis ATPase; 7, E. coli polyP digested with M. bovis ATPase; 8, P. aeruginosa polyP digested with M. bovis ATPase.