Publications [#232704] of Katherine J. Franz

Journal Articles

  1. Hyman, LM; Stephenson, CJ; Dickens, MG; Shimizu, KD; Franz, KJ, "Toward the development of prochelators as fluorescent probes of copper-mediated oxidative stress.", Dalton Transactions (Cambridge, England : 2003)January,, 2010, 10.1039/b914568k(2), 568-576 [20023995], [doi].
    (last updated on 2023/01/01)

    Abstract:
    A fluorescent sensor prochelator, FlamB (fluorescein hydrizido 2-imidophenylboronic ester), has been developed that selectively probes for copper under conditions of oxidative stress. High levels of hydrogen peroxide trigger the release of a boronic ester masking group from the prochelator to unveil a metal chelator, FlamS (fluorescein hydrizido 2-imidophenol), that provides a modest fluorescence increase in response to Cu(2+) but not other metal ions. X-Ray crystal structures of FlamB, FlamS, and Cu-bound FlamS are all reported. The fluorescence turn-on results from opening of a fluorescein spirolactam ring upon Cu(2+) binding to FlamS in aqueous solution. Oxidation of the aryl boronic ester of FlamB to the metal-binding phenol of FlamS proceeds in organic solvents. However, in aqueous solution a competing mechanism occurs due to hydrolytic instability of the masked prochelator. Hydrolysis of FlamB leads to formation of fluorescein hydrazide, which interacts with copper or H(2)O(2) to produce fluorescein and a significant fluorescence increase.