テルビウム（III）-芳香族ポリアミノカルボン酸エステル系を用いるエステラーゼ活性の蛍光定量法

抄録

Enzyme-amplified lanthanide luminescence (EALL) is a promising method which has been developed for enzymatically amplified signal detection. A signal is generated by enzymatically transforming a substrate into a product, which forms a fluorescent lanthanide chelate. With the aim of establishing a new EALL detection system, we focused on O,O'-bis(2-aminophenyl)ethyleneglycol-N,N,N',N'-tetraacetic acid (BAPTA), which is known to be a specific chelator for calcium. BAPTA also forms some energy-transfer fluorescent complexes with lanthanide ions at physiological pH, and functions as a good sensitizer, especially for terbium(III) ion. Thus, we examined whether esterase activity can be determined by EALL detection where BAPTA and its tetraacetoxymethyl ester (BAPTA-AM) are used as the Tb(III) chelate and the reaction substrate, respectively. Regarding the rate of the Tb(III) fluorescent intensity changing per unit time (ΔI/Δt) as an initial rate of the enzymatic reaction, the determination of esterase activity was successful in the range of 0.010∼0.10 u/mL. Within this work, the suitability of the Tb(III)/BAPTA-AM system for EALL detection has been proven for determining esterase activity.