Lanthanide Catalyzed Cyclization of Uridine 3'-p-Nitrophenyl Phosphate.
Steady state kinetics and (15)N isotope effects have been used to study the cyclization reaction of uridine 3'-p-nitrophenyl phosphate. The cyclization reaction is catalyzed by transition metal ions and lanthanides, as are substitution reactions of many phosphate esters. Kinetic analysis reveals that the erbium-catalyzed cyclization reaction involves the concerted deprotonation of the 2'-OH group and departure of the leaving group. The transition state is very late, with a very large degree of bond cleavage to the leaving group, which could be due to a large degree of polarization of the P&bond;O bonds by erbium. Copyright 2000 Academic Press.
Rishavy
MA
Institute for Enzyme Research, University of Wisconsin at Madison, Wisconsin, 53705
Hengge
AC
Cleland
WW