Figure 7.

Electron transfer efficiency in the D231A/H314A mutant and WT human CYP51. A, enzymatic reduction with NADPH in the presence of CPR. Left, spectral changes introduced by binding of carbon monoxide to the ferrous CYP51. Right, efficiency of enzymatic reduction relative to the chemical reduction with sodium dithionite. B, NADPH oxidation. Left, decrease of the 340-nm absorbance upon NADPH consumption. Left, a sample of absorbance spectra; right, time course graphs. Right, rates of NADPH consumption. The mixture contained 2 μm CYP51, 4 μm CPR, 150 μm NADPH, and either 0 or 8 μm lanosterol (S); n = 2 ± S.D.