Figure 2.

Inhibition of NADPH- or NADH-dependent cytochrome P450 reductase activities by nucleotide analogues. Cytochrome c reduction was measured as described in the legend to Table 1 by using CPR with NADPH (15 μM, filled symbols) or W676A with NADH (300 μM, open symbols). The concentrations of NADPH and NADH corresponded to the respective apparent K_M values (Table 3). Inhibition studies were performed with 2′-AMP (1 μM–0 mM, squares), NADH (100 μM–10 mM, filled circle) and NADPH (10 nM–100 μM, open circle).