J. Biol. Chem., Vol. 255, Issue 20, 9545-9548, Oct, 1980
ATP formation from adenyl-5'-yl imidodiphosphate, a nonhydrolyzable ATP analog
SM Penningroth, K Olehnik and A Cheung
The purity of several preparations of adenyl-5'-yl imidodiphosphate
(AMP-PNP) was analyzed using thin layer chromatography and the
luciferin-luciferase assay. Three contaminants were identified: adenyl-
5'-yl phosphoramidate, phosphorylated AMP-PNP, and ATP. The level of ATP
contamination ranged from 0.02% to 0.3% in commercially obtained AMP-PNP
preparations, and rose to 10% following incubation of AMP-PNP at 37 degrees
C for 3 weeks in aqueous solution. The chemistry of the phosphoramidate
bond is reviewed briefly, and evidence for a simple mechanism for the
spontaneous formation of ATP from AMP-PNP is presented.