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A Cell-Permeable Fluorescent Prochelator Responds to Hydrogen Peroxide and Metal Ions by Decreasing Fluorescence.

Publication ,  Journal Article
Hyman, LM; Franz, KJ
Published in: Inorganica chimica acta
January 2012

Described here is the development of two boronic ester-based fluorescent prochelators, FloB (2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)-4(5)-[2-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzylidene-hydrazinocarbonyl]-benzoic acid) and FloB-SI (2-(6-hydroxy-3-oxo-3Hxanthen-9-yl)-4(5)-[2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyloxy)-benzylidene-hydrazinocarbonyl]-benzoic acid) that show a fluorescence response to a variety of transition metal ions only after reaction with H(2)O(2). Both prochelators' boronic ester masks are oxidized by H(2)O(2) to reveal a fluorescein-tagged metal chelator, FloS (4(5)-(2-hydroxy-benzylidenehydrazinocarbonyl)-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)-benzoic acid). Chelation of Fe(3+) or Cu(2+) elicits a 70% decrease in the emission signal of FloS, while Zn(2+), Ni(2+), and Co(2+) produce a more modest fluorescence decrease. The conversion of FloB to FloS proceeds in organic solvents, but hydrolytic decomposition of its hydrazone backbone is observed in aqueous solution. However, FloB-SI oxidizes cleanly with H(2)O(2) within 1 h in aqueous solutions to produce FloS. Fluorescence microscopy studies in HeLa cells with FloB-SI show that the sensor's fluorescence intensity remains unchanged until incubation with exogenous H(2)O(2), which results in a decreased fluorescent signal. Incubation with a competitive chelator restores the emission response, thus suggesting that FloB-SI can effectively report on a H(2)O(2)-induced increase in intracellular labilized metal.

Duke Scholars

Published In

Inorganica chimica acta

DOI

ISSN

0020-1693

Publication Date

January 2012

Volume

380

Start / End Page

125 / 134

Related Subject Headings

  • Inorganic & Nuclear Chemistry
  • 3402 Inorganic chemistry
  • 0399 Other Chemical Sciences
  • 0306 Physical Chemistry (incl. Structural)
  • 0302 Inorganic Chemistry
 

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Hyman, L. M., & Franz, K. J. (2012). A Cell-Permeable Fluorescent Prochelator Responds to Hydrogen Peroxide and Metal Ions by Decreasing Fluorescence. Inorganica Chimica Acta, 380, 125–134. https://doi.org/10.1016/j.ica.2011.11.056
Journal cover image

Published In

Inorganica chimica acta

DOI

ISSN

0020-1693

Publication Date

January 2012

Volume

380

Start / End Page

125 / 134

Related Subject Headings

  • Inorganic & Nuclear Chemistry
  • 3402 Inorganic chemistry
  • 0399 Other Chemical Sciences
  • 0306 Physical Chemistry (incl. Structural)
  • 0302 Inorganic Chemistry