The pseudo-first-order rate constants (kh) for transesterification of adenylyl-3', 5'-uridine 3'- monophosphate (ApUp) by Zn-([9] aneN#+(I), Zn ([12] aneN3) 2+(2), or Zn (cyclam) 2+(3) in water at 64 OC, pH= 7.6, follow the order 1= 2> 3 ([9] aneN3= 1, 4, 7-triazacyclononane,[12] aneN3= 1, 5, 9-triazacyclododecane, cyclam= 1, 4, 8, 11-tetraazacyclotetradecane). Catalytic behavior is observed for transesterification of ApUp by 1; five turnovers of I were ...