Kinetics-Based Quantification of Peroxynitrite Using the Oxidative Decarbonylation of Isatin

Peroxynitrite and its radical decomposition
products are highly
reactive nitrogen and oxygen species that can influence the balance
between health and disease in multiple organ systems. Despite vigorous
research activity, real-time quantitative monitoring of peroxynitrite
generated by donor compounds remains challenging. Here, we report
a kinetics-based fluorescence method for quantitative tracking of
peroxynitrite generation using the oxidative decarbonylation of isatin
to form anthranilic acid as a fluorescent probe. This method relies
on knowledge of the rate of the reaction of peroxynitrite with the
probe, which we measure using stopped-flow fluorescence techniques.
To the best of our knowledge, this is the first optical method capable
of providing real-time quantitative measures of peroxynitrite concentrations
generated from donor compounds, as demonstrated herein for SIN-1 and
Angeli’s salt.