Analytical Sciences

A “Turn-On” Fluorescent Chemosensor Based on Peptidase for Detecting Copper(II)

Xiao-Li LV,* Yun WEI,** and Shi-Zhong LUO*

*Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, P. R. China
**State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, P. R. China

A new fluorescent chemosensor for Cu(II) ions was designed and synthesized on the basis of the sequence-specific cleavage of the peptide bond by the peptidase (metal or metal complexes). In the chemosensor system, the substrate was labeled with a FAM fluorophore (6-carboxyfluorescein) at the N-terminal and with a Dabcyl quencher 4-(4′-dimethylaminophenylazo)benzoic acid at the ε-N of C-terminal Lys. In the presence of Cu(II), the substrate strand is cleaved, and the release of the cleaved fragment results in a significant fluorescence increase. The design was aided by the FRET study that showed a “turn-on” response for Cu(II) in an aqueous medium. Under optimum conditions, the novel chemosensor described here had a linear response range for Cu(II) from 1.0 × 10⁻⁸ to 1.0 × 10⁻⁶ mol dm⁻³ with a detection limit of 1.0 × 10⁻⁸ mol dm⁻³.

J-STAGE: View this article in J-STAGE