Characterization of the ATP-Dependent Lon-Like Protease in Methanobrevibacter smithii

Figure 3

Lon-like-Ms activity assay. (a) Time courses of fluorogenic peptide (A) and α-casein (B) hydrolysis by Lon-like-Ms. Reactions were conducted in 50 mM Tris-HCl buffer (pH 8.0) containing 5 μg of Lon-like-Ms and 0.3 mM Glt-AAF-MNA at 37°C. ATP and/or MgCl₂ were added to the mixture as follows: 4 mM ATP and 10 mM MgCl₂ (filled triangle); no addition (filled quadrangle); 10 mM MgCl₂ (filled cycle); or 4 mM ATP (filled diamond). (b) Effects of temperature (A) and pH (B) on the peptide cleavage activity of Lon-like-Ms. Glt-AAF-MNA was used as a substrate for the peptide cleavage assay. (c) Effects of ATP (filled triangle) and AMP-PNP (filled quadrangle) concentrations on the peptide cleavage activity of Lon-like-Ms.

(a)

(b)

(c)