title: Tetrakis(2-quinolinylmethyl)ethylenediamine (TQEN) as a new fluorescent sensor for zinc.
abstract: A new fluorescent sensor for zinc that binds 1 equivalent of zinc ion, N,N,N',N'-tetrakis(2-quinolylmethyl)ethylenediamine (TQEN), has been prepared and characterized. Zinc-bound TQEN exhibits fluorescence around 383 nm upon excitation at 317 nm, while free TQEN emits very weak fluorescence. UV-Vis and 1H NMR spectral changes also detected the binding of TQEN with zinc ion. The crystal structure of zinc complex with TQEN was determined by X-ray crystallography and compared with that of the TPEN-Zn complex (TPEN =N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine). The binding affinity of TQEN with zinc ion is very high (Kd < 1 microM in aqueous dmf solution). Competition experiments reveal that the zinc-binding affinity of TQEN is lower than the parent, strong metal ion chelator TPEN, and comparable to EGTA (EGTA = ethylene glycol-bis(2-aminomethyl)-N,N,N',N'-tetraacetic acid).
authors.affiliation: KYOUSEI Science Center and Division of Material Science, Nara Women's University, Nara 630-8506, Japan. mikata@cc.nara-wu.ac.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mikata
authors.forename: Motoko
authors.initials: M
authors.lastname: Wakamatsu
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yano
mesh_terms: D015374:Biosensing Techniques; D018360:Crystallography, X-Ray; D004533:Egtazic Acid / Q000737:chemistry / Q000378:metabolism; D005029:Ethylenediamines / Q000737:chemistry* / Q000378:metabolism; D005456:Fluorescent Dyes / Q000737:chemistry*; D008956:Models, Chemical; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism; D017967:Zinc Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism
chemical_list: D005029:Ethylenediamines; D005456:Fluorescent Dyes; D017967:Zinc Compounds; D004533:Egtazic Acid; D015032:Zinc; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine