Figure 2.

Quenching of ¹O₂ phosphorescence by pyridoxine. (A) Spectrum of ¹O₂ phosphorescence after irradiation of a solution of cercosporin (Inset) in aerobic D₂O. (B) ¹O₂ phosphorescence decay observed at the maximum of ¹O₂ emission after one-shot laser ¹O₂ production in the absence (−pyridoxine) and presence (+pyridoxine) of 0.1 mM pyridoxine. (C) Observed rate constant for ¹O₂ quenching as a function of the increasing concentration of pyridoxine (Inset) and pyridoxal 5-phosphate at pD 7.4 in D₂O aerobic phosphate buffer (20 mM). The line slopes yield the quenching-rate constants (Table 3). Rose bengal (50 μM) was used to photosensitize ¹O₂.