Fig. 1.

Reaction of the fully reduced liposome-reconstituted cbb₃ with O₂ or NO in the flow-flash reaction. A laser flash initiates the reaction at t = 0. Shown are the absorbance changes at 430, 420, 550 (reporting oxidation of the c-type hemes), and 560 nm (reporting on the b-type hemes). Experimental conditions: ≈1.4 μM cbb₃ after mixing (1:1), 25 mM Hepes, pH 7.5, 100 mM KCl, [O₂] = 0.6 mM or [NO] = 1 mM, T = 298 K. For other experimental details, see text.