FIG 5.

Spectral changes during the transformation of 2C4NP by purified H₆-PnpA. Sample and reference cuvettes contained 0.1 mM NADPH, 0.03 mM flavin adenine dinucleotide, 50 mM phosphate buffer (pH 7.4), and 10 μg H₆-PnpA in a 0.5-ml volume. The reaction was initiated by the addition of 25 μM 2C4NP, and the spectra were recorded every minute after the addition of 2C4NP. The arrows indicate the directions of spectral changes.