Journal: ACS chemical biology

Article Title: Active-site directed chemical tools for profiling mitochondrial Lon protease

doi: 10.1021/cb100408w

Figure Lengend Snippet: (a) Representative time course of peptide cleavage by human Lon in the presence of ATP and DBN93. Two rates of cleavage, vi and vss, and a rate constant of interconversion between the two, kinter, can be quantified from the experimental time course. (b) Reactions containing 150 nM human Lon were preincubated with 1 mM FRETN 89–98 prior to the addition of 1 mM ATP. After 90 s, varying amounts of DBN93 (0–2 µM) were added and peptide hydrolysis was monitored over 45 min. All experiments were done in at least duplicate and the vi and vss values determined by fitting the time courses as done previously for bacterial Lon (23). The averaged vi (■), vss (▲) in the presence of inhibitor normalized to 1 with the average velocity in the absence of inhibitor were plotted against corresponding inhibitor concentrations. The solid lines represent the best fit of the data, as described in Materials and Methods. (c) Experimental time courses were fit to both one-step and two-step inhibition mechanisms using the global non-linear fitting program, DynaFit (Biokin, Ltd.). Black lines represent the averaged experimental time courses at 150 nM hLon, 1 mM ATP, 1 mM peptide and varying concentrations of DBN93. Gray lines represent the best fit of the data to the two-step time-dependent mechanism which was most consistent with the experimental data. The kinetic parameters yielded from this fit are summarized and compared to those previously determined for bacterial Lon (23) in Table 1.

Article Snippet: The solid lines represent the best fit of the data, as described in Materials and Methods. ( c ) Experimental time courses were fit to both one-step and two-step inhibition mechanisms using the global non-linear fitting program, DynaFit (Biokin, Ltd.).

Techniques: Inhibition

Journal: ACS chemical biology

Article Title: Active-site directed chemical tools for profiling mitochondrial Lon protease

doi: 10.1021/cb100408w

Figure Lengend Snippet: Kinetic parameters of inhibition of human Lon peptidase activity by DBN93 as determined by global fitting of experimental data using DynaFit. The resultant values are compared to those previously determined for bacterial Lon. Reported errors are s.e.m.

Article Snippet: The solid lines represent the best fit of the data, as described in Materials and Methods. ( c ) Experimental time courses were fit to both one-step and two-step inhibition mechanisms using the global non-linear fitting program, DynaFit (Biokin, Ltd.).

Techniques: Inhibition, Activity Assay

Journal: ACS chemical biology

Article Title: Active-site directed chemical tools for profiling mitochondrial Lon protease

doi: 10.1021/cb100408w

Figure Lengend Snippet: (a) Representative time course of peptide cleavage by human Lon in the presence of ATP and DBN93. Two rates of cleavage, vi and vss, and a rate constant of interconversion between the two, kinter, can be quantified from the experimental time course. (b) Reactions containing 150 nM human Lon were preincubated with 1 mM FRETN 89–98 prior to the addition of 1 mM ATP. After 90 s, varying amounts of DBN93 (0–2 µM) were added and peptide hydrolysis was monitored over 45 min. All experiments were done in at least duplicate and the vi and vss values determined by fitting the time courses as done previously for bacterial Lon (23). The averaged vi (■), vss (▲) in the presence of inhibitor normalized to 1 with the average velocity in the absence of inhibitor were plotted against corresponding inhibitor concentrations. The solid lines represent the best fit of the data, as described in Materials and Methods. (c) Experimental time courses were fit to both one-step and two-step inhibition mechanisms using the global non-linear fitting program, DynaFit (Biokin, Ltd.). Black lines represent the averaged experimental time courses at 150 nM hLon, 1 mM ATP, 1 mM peptide and varying concentrations of DBN93. Gray lines represent the best fit of the data to the two-step time-dependent mechanism which was most consistent with the experimental data. The kinetic parameters yielded from this fit are summarized and compared to those previously determined for bacterial Lon (23) in Table 1.

Article Snippet: To support the two-step mechanism, the experimental time courses were globally fitted to both a one- and a two-step inhibition mechanism using the nonlinear fitting program Dynafit (Biokin) ( 26 ) ( , panel c ).

Techniques: Inhibition

Journal: ACS chemical biology

Article Title: Active-site directed chemical tools for profiling mitochondrial Lon protease

doi: 10.1021/cb100408w

Figure Lengend Snippet: Kinetic parameters of inhibition of human Lon peptidase activity by DBN93 as determined by global fitting of experimental data using DynaFit. The resultant values are compared to those previously determined for bacterial Lon. Reported errors are s.e.m.

Article Snippet: To support the two-step mechanism, the experimental time courses were globally fitted to both a one- and a two-step inhibition mechanism using the nonlinear fitting program Dynafit (Biokin) ( 26 ) ( , panel c ).

Techniques: Inhibition, Activity Assay