Flux of intracellular labile zinc during apoptosis (gene-directed cell death) revealed by a specific chemical probe, Zinquin

Chem Biol. 1994 Nov;1(3):153-61. doi: 10.1016/1074-5521(94)90005-1.


Background: The transition metal Zn(II) is thought to regulate cell and tissue growth by enhancing mitosis (cell proliferation) and suppressing the counterbalancing process of apoptosis (gene-directed cell death). To investigate the role of Zn(II) further, we have used a UV-excitable Zn(II)-specific fluorophore, Zinquin. The ester group of Zinquin is hydrolyzed by living cells, ensuring its intracellular retention; this allows the visualization and measurement of free or loosely-bound (labile) intracellular Zn(II) by fluorescence video image analysis or fluorimetric spectroscopy.

Results: Here we show that in cells undergoing early events of apoptosis, induced spontaneously or by diverse agents, there is a substantial increase in their Zinquin-detectable Zn(II). This increase occurred in the absence of exogenous Zn(II) and before changes in membrane permeability, consistent with a release of Zn(II) from intracellular stores or metalloproteins rather than enhanced uptake from the medium. We propose that there is a major redistribution of Zn(II) during the induction of apoptosis, which may influence or precipitate some of the later biochemical and morphological changes.

Conclusions: The phenomenon of Zn(II) mobilization, revealed by Zinquin, presents a new element in the process of apoptosis for investigation and may permit rapid and sensitive identification of apoptotic cells, particularly in those tissues where their frequency is low.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Fluorescent Dyes
  • Microscopy, Video
  • Quinolones
  • Rats
  • Rats, Sprague-Dawley
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / ultrastructure
  • Tosyl Compounds
  • Zinc / metabolism
  • Zinc / physiology*


  • Fluorescent Dyes
  • Quinolones
  • Tosyl Compounds
  • Zinc
  • zinquin