In contrast to the other three TmNMPKs, all uridine analogs were accepted by TmTMPK and TmUMPK (Figure ). Notably, for 5-Br-UMP only the diphosphate was detected. This might be explained by substrate scope observed for both NMPKs. Neither of the two enzymes was able to convert UDP to UTP (Figure ). Interestingly, for the other uridine analogs the triphosphate was formed. Thus, TmAcK very likely accepted the modified uridine diphosphates, except for 5-Br-UDP, as substrates.