Fig. 1. Response of PNCL to ONOO^–. (A) Chemiluminescent emission spectra of 20 μM PNCL and 0 (blue trace), 5, 10, 20, 40, 80, 100, 200 μM (red trace) ONOO^–. (B) Time scans of the chemiluminescent emission at 525 nm of 20 μM PNCL and 0 (blue trace), 5, 10, 20, 40, 80, 100, 200 μM (red trace) ONOO^–. (C) Peak emission intensity at 525 nm of 20 μM PNCL after adding 0–200 μM ONOO^–. (D) Time scan of the chemiluminescent emission at 525 nm of 20 μM PNCL and 200 μM SIN-1. All experiments were performed in 20 mM HEPES (pH 7.4), containing <1% DMSO.