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. Author manuscript; available in PMC: 2008 Feb 29.
Published in final edited form as: Biochemistry. 2007 Aug 31;46(38):10971–10978. doi: 10.1021/bi7009822

Figure 4.

Figure 4

Effect of ADP-ribose on irreversible inhibition of complex I by NADH-OH. (A) SMPs (25 μg/mL) were incubated for 1 min in the standard reaction mixture containing 28 nM NADH-OH and ADP-ribose (concentrations are indicated on the abscissa). The residual NADH oxidase activities (100 μM NADH and 0.05 μg/mL gramicidin D) were determined. The pseudo-first-order rate constants for NADH-OH-induced inhibition were calculated as kobs = ln(v0/v t) and plotted as a function of ADP-ribose concentration. v0 corresponds to the rate of NADH oxidation in the absence of NADH-OH, and vt is the residual activity after 1 min of incubation with NADH-OH. (B) Secondary plot of 1/kobs versus ADP-ribose concentration used to determine KD for ADP-ribose.