FIGURE 5.

Reduction of FMN in the FMN domain of nNOS ΔG810 mutant (11 μm) by excess (∼300 μm) of dithionite. The spectral changes in the range of 350–570 nm were monitored at two different pH values, pH 7.0 (A) and pH 9.0 (B), using a photodiode array detector on a stopped flow spectrophotometer. For clarity, only a few scans selected out of total of 500 scans at various time points are displayed. Note the slower build-up of 391 nm peak at pH 9.0. Also, the total bleaching of the 468 nm peak is within 500 s at pH 7.0 but takes ∼1000 s at pH 9.0.