Table 2.

Protease and ATPase activities of pure Lon proteins

Protein	Protease activity		ATPase activity
	pmol/pmol per min	%	pmol/pmol per min	%
Lon	0.290  ±  0.014	(100)	37.1  ±  7.3	(100)
LonK638N	0.009  ±  0.005	3	4.4  ±  1.3	12
LonS1015A	0.007  ±  0.002	2	15.1  ±  3.2	41
LonΔcharge	0.162  ±  0.065	56	17.7  ±  4.7	48

Protease activity: pmol of casein hydrolyzed per pmol of monomer per min at 37°C in the presence of 5 mM ATP/20 mM Tris, pH 8.0/10 mM MgCl₂/50 μg of casein/0.5 μg of Lon in 200 μl per time point. In the absence of ATP, less than 3% of wild-type activity was observed for Lon and all of the Lon variants. ATPase activity: pmol of ATP hydrolyzed per pmol of Lon monomer per min at 37°C in the presence of 1 mM ATP/20 mM Tris, pH 8.0/10 mM MgCl₂/0.5 or 1 μg of Lon in 30 μl per time point.