Fragmentation and rearrangement patterns of phospho‐ureas. Possible consequences for biotin activation

Analysis by electron impact and metastable ions (MIKE technique) of the fragmentation patterns for one acyclic and two cyclic N-phosphorylated ureas reveals for the first case an isomerization from nitrogen to the ureido oxygen atom of the phosphoryl group and subsequent fragmentation. For the other two cases, fragments result from PN bond breaking and ring-opening. Possible involvement in the biotin-ATP activation process is discussed.