A new water-soluble fluorescent Cu(II) chemosensor based on tetrapeptide histidyl-glycyl-glycyl-glycine (HGGG)

Abstract

A new water-soluble fluorescent chemosensor Fluor-HGGG was synthesized by linking a tetrapeptide histidyl-glycyl-glycyl-glycine (HGGG) with fluorescein via standard solid-phase 9-fluorenylmethoxycarbonyl (Fmoc) chemistry. Significant fluorescence quenching was observed with Fluor-HGGG in the presence of Cu(2+). Other metal ions including Ag(+) Ca(2+), Cd(2+), Co(2+), Fe(2+), Fe(3+), Hg(2+), Mn(2+), Ni(2+) and Zn(2+) produced only minor changes in fluorescence values for the system. The dissociation constant (K(D)) of Cu(2+) binding in Fluor-HGGG was found to be 37 mu M. The maximum fluorescence quenching caused by Cu(2+) binding in Fluor-HGGG was observed over the pH range 7-7.5. (C) 2009 Elsevier B.V. All rights reserved.