TABLE 2.

Relative activities of RNase E point mutants

Enzymea	Kinetic constantsb
	Km	kcat
	nm	min−1
WT	33	11
WTc	5100	0.95
F57A	120	1.9
F67A	320	1.1
R169Q	350	0.28
D303A	38	0.008
D346A	77	0.007

^a In all cases, the enzyme includes residues 1–529 of RNase E.

^b Except where noted, kinetic constants were estimated from Eadie-Hofstee plots of data generated with 5′-P-BR14FD as substrate (“Experimental Procedures”). Rates for each substrate concentration were determined at least in triplicate, then averaged prior to plotting.

^c Data on this line were obtained with 5′-OH- BR14FD as substrate (“Experimental Procedures”).