Dizinc Phosphohydrolase Model Built on a m-Terphenyl Scaffold and Its Use in Indicator Displacement Assays for Pyrophosphate Under Physiological Conditions

A dinucleating ligand (1,3-bis[2-(di-2-picolylaminomethyl)-phenyl]benzene, L2} built on a m-terphenyl scaffold was prepared. The dissociation constants for the dizinc complex of L2 (Zn(2)L2) binding to phosphate, pyrophosphate and commercially available complexometric indicators were determined under physiological pH [10 mm N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) buffer at pH 7.4]. Colorimetric and fluorescence-based indicator displacement assays with selectivity for pyrophosphate over other anions were achieved with Zn(2)L2 as the receptor component. These assays show good response characteristics for quantification of pyrophosphate concentrations as low as 2.5 x 10(-6) m, suggesting their utility for measuring pyrophosphate levels in synovial fluid. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)