Construction of a Turn Off-On-Off Fluorescent System Based on Competitive Coordination of Cu²⁺ between 6,7-Dihydroxycoumarin and Pyrophosphate Ion for Sensitive Assay of Pyrophosphatase Activity

Figure 7

Fluorescence changes of DHC (500 μM, curve A) in the absence (curve A) and presence of various anions (curves B to P: Cl⁻, F⁻, Br⁻, I⁻, , , , , , ATP, AMP, ADP, PPi, , , , and PPi, 200 μM) in HEPES buffer aqueous solution (10 mM, pH 6.5). Other reaction conditions are the same as Figure 1.