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 len gth was found to vary surprisingly little. In sharp contrast, the hydrolyti c activity of these catalysts against bis(p-nitrophenyl)-phosphate (BNPP) v aried 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 u ntil now was established only in some enzymes, Other than with BNPP, the hy drolysis with plasmid DNA (nicking experiments) showed no rate enhancement.