NADPH-cytochrome c oxidoreductase obtained from the cells of Thiobacillus thiooxidans displayed the pH optimum of 8.7 and was completely inactivated by heating at 60°C for 10 min. Enzymatic activity was proportional to protein concentration and linear with time. The Km for NADPH was found to be 2.13×10-5M. The enzyme was specific for NADPH and transferred electrons to cytochrome c and some dyes. p-Chloromercuribenzoate, EDTA and acryflavin inhibited the reductase activity.
