Carboxylic groups as cofactors in the lanthanide-catalyzed hydrolysis of phosphate esters.: Stabilities of europium(III) complexes with aza-benzo-15-crown-5 ether derivatives and their catalytic activity vs bis(p-nitrophenyl)phosphate and DNA

[GRAPHICS] The stability of europium(III) complexes with benzocrown ether derivatives 2-4 containing carboxylic functions with methylene spacers of different length was found to vary surprisingly little. In sharp contrast, the hydrolytic activity of these catalysts against bis(p-nitrophenyl)-phosphate (BNPP) varied by a factor of 30. The results show for the first time the efficiency of the carboxylic group as cofactor in phosphate ester hydrolysis, which until now was established only in some enzymes, Other than with BNPP, the hydrolysis with plasmid DNA (nicking experiments) showed no rate enhancement.